Hydraulic machinery are machines and tools which use fluid power to do work. Heavy equipment is a common example.

In this type of machine, high-pressure liquid - called hydraulic fluid - is transmitted throughout the machine to various hydraulic motors and hydraulic cylinders. The fluid is controlled directly or automatically by control valves and distributed through hoses and tubes.

The popularity of hydraulic machinery is due to the very large amount of power that can be transferred through small tubes and flexible hoses, and the high power density and wide array of actuators that can make use of this power.

Hydraulic machinery is operated by the use of hydraulics, where a liquid is the powering medium. Pneumatics, on the other side, is based on the use of a gas as the medium for power transmission, generation and control.

Hydraulic circuits

For the hydraulic fluid to do work, it must flow to the actuator and or motors, then return to a reservoir.

The fluid is then filtered and re-pumped. The path taken by hydraulic fluid is called a hydraulic circuit of which there are several types. Open center circuits use pumps which supply a continuous flow. The flow is returned to tank through the control valve's open center; that is, when the control valve is centered, it provides an open return path to tank and the fluid is not pumped to a high pressure. Otherwise, if the control valve is actuated it routes fluid to and from an actuator and tank. The fluid's pressure will rise to meet any resistance, since the pump has a constant output. If the pressure rises too high, fluid returns to tank through a pressure relief valve.

Open and closed circuits

Open-loop: Pump-inlet and motor-return (via the directional valve) are connected to the hydraulic tank.The term loop applies to feedback; the more correct term is open versus closed "circuit".

Closed-loop: Motor-return is connected directly to the pump-inlet. To keep up pressure on the low pressure side, the circuits have a charge pump that supplies cooled and filtered oil to the low pressure side. Closed-loop circuits are generally used for hydrostatic transmissions in mobile applications.

Advantages: No directional valve and better response, the circuit can work with higher pressure. The pump swivel angle covers both positive and negative flow direction. Disadvantages: The pump cannot be utilized for any other hydraulic function in an easy way and cooling can be a problem due to limited exchange of oil flow. High power closed loop systems generally must have a 'flush-valve' assembled in the circuit in order to exchange much more flow than the basic leakage flow from the pump and the motor, for increased cooling and filtering. The flush valve is normally integrated in the motor housing to get a cooling effect for the oil that is rotating in the motorhousing itself.

Closed loop systems in mobile equipment are generally used for the transmission as an alternat[FS:PAGE]ive to mechanical and hydrodynamic (converter) transmissions. The advantage is a stepless gear ratio and a more flexible control of the gear ratio depending on the load and operating conditions. The hydrostatic transmission is generally limited to around 200 kW max.

Hydraulic pump

Hydraulic pumps supply fluid to the components in the system. Pressure in the system develops in reaction to the load. Hence, a pump rated for 5,000 psi is capable of maintaining flow against a load of 5,000 psi.Pumps have a power density about ten times greater than an electric motor (by volume). They are powered by an electric motor or an engine, connected through gears, belts, or a flexible elastomeric coupling to reduce vibration.

Common types of hydraulic pumps to hydraulic machinery applications are;

Gear pump: cheap, durable, simple. Less efficient, because they are constant displacement, and mainly suitable for pressures below 20 MPa (3000 psi).

Vane pump: cheap and simple, reliable (especially in g-rotor form). Good for higher-flow low-pressure output.

Axial piston pump: many designed with a variable displacement mechanism, to vary output flow for automatic control of pressure. There are various axial piston pump designs, including swashplate and checkball. The most common is the swashplate pump.

Radial piston pump: A pump that is normally used for very high pressure at small flows.

Piston pumps are more expensive than gear or vane pumps, but provide longer life operating at higher pressure, with difficult fluids and longer continuous duty cycles. Piston pumps make up one half of a hydrostatic transmission.

Control valves

Directional control valves route the fluid to the desired actuator. They usually consist of a spool inside a cast iron or steel housing.

Directional control valves are usually designed to be stackable, with one valve for each hydraulic cylinder, and one fluid input supplying all the valves in the stack.

The spool position may be actuated by mechanical levers, hydraulic pilot pressure, or solenoids which push the spool left or right.

The main valve block is usually a stack of off the shelf directional control valves chosen by flow capacity and performance. Some valves are designed to be proportional (flow rate proportional to valve position), while others may be simply on-off. The control valve is one of the most expensive and sensitive parts of a hydraulic circuit.

Pressure relief valves are used in several places in hydraulic machinery; on the return circuit to maintain a small amount of pressure for brakes, pilot lines, etc... On hydraulic cylinders, to prevent overloading and hydraulic line rupture. On the hydraulic reservoir, to maintain a small positive pressure which excludes moisture and contamination.

Pressure reducing valves reduce the supply pressure as needed for various circuits.

Check valves are one-way valves, allowing an accumulator to charge and maintain its pressure after the machine is turned off, for [FS:PAGE]example.

Pilot controlled Check valves are one-way valve that can be opened (for both directions) by a foreign pressure signal. For instance if the load should not be hold by the check valve anymore. Often the foreign pressure comes from the other pipe that is connected to the motor or cylinder.

Counterbalance valves are in fact a special type of pilot controlled check valve. Whereas the check valve is open or closed, the counterbalance valve acts a bit like a pilot controlled flow control.

Cartridge valves are in fact the inner part of a check valve; they are off the shelf components with a standardized envelope, making them easy to populate a proprietary valve block. They are available in many configurations; on/off, proportional, pressure relief, etc. They generally screw into a valve block and are electrically controlled to provide logic and automated functions.

Hydraulic fuses are in-line safety devices designed to automatically seal off a hydraulic line if pressure becomes too low, or safely vent fluid if pressure becomes too high.

Auxiliary valves. Complex hydraulic systems will usually have auxiliary valve blocks to handle various duties unseen to the operator, such as accumulator charging, cooling fan operation, air conditioning power, etc. They are usually custom valves designed for the particular machine.

Reservoir

The hydraulic fluid reservoir holds excess hydraulic fluid to accommodate volume changes from: cylinder extension and contraction, temperature driven expansion and contraction, and leaks. The reservoir is also designed to aid in separation of air from the fluid and also work as a heat accumulator to cover losses in the system when peak power is used. Design engineers are always pressured to reduce the size of hydraulic reservoirs, while equipment operators always appreciate larger reservoirs.

Some designs include dynamic flow channels on the fluid's return path that allow for a smaller reservoir.

Accumulators

Accumulators are a common part of hydraulic machinery. Their function is to store energy by using pressurized gas. One type is a tube with a floating piston. On one side of the piston is a charge of pressurized gas, and on the other side is the fluid. Bladders are used in other designs. Reservoirs store a system's fluid.

Hydraulic fluid

Also known as tractor fluid, hydraulic fluid is the life of the hydraulic circuit. It is usually petroleum oil with various additives. Some hydraulic machines require fire resistant fluids, depending on their applications. In some factories where food is prepared, water is used as a working fluid for health and safety reasons.

In addition to transferring energy, hydraulic fluid needs to lubricate components, suspend contaminants and metal filings for transport to the filter, and to function well to several hundred degrees Fahrenheit or Celsius.

Filters

Filters are an important part of hydraulic systems. Metal particles are continually produced by mechanical co[FS:PAGE]mponents and need to be removed along with other contaminants.

Filters may be positioned in many locations. The filter may be located between the reservoir and the pump intake. Blockage of the filter will cause cavitation and possibly failure of the pump. Sometimes the filter is located between the pump and the control valves. This arrangement is more expensive, since the filter housing is pressurized, but eliminates cavitation problems and protects the control valve from pump failures. The third common filter location is just before the return line enters the reservoir. This location is relatively insensitive to blockage and does not require a pressurized housing, but contaminants that enter the reservoir from external sources are not filtered until passing through the system at least once.

Tubes, Pipes and Hoses

Hydraulic tubes are seamless steel precision pipes, specially manufactured for hydraulics. The tubes have standard sizes for different pressure ranges, with standard diameters up to 100 mm. The tubes are supplied by manufacturers in lengths of 6 m, cleaned, oiled and plugged. The tubes are interconnected by different types of flanges (especially for the larger sizes and pressures), welding cones/nipples (with o-ring seal),

several types of flare connection and by cut-rings. In larger sizes, hydraulic pipes are used. Direct joining of tubes by welding is not acceptable since the interior cannot be inspected.

Hydraulic pipe is used in case standard hydraulic tubes are not available. Generally these are used for low pressure. They can be connected by threaded connections, but usually by welds. Because of the larger diameters the pipe can usually be inspected internally after welding. Black pipe is non-galvanized and suitable for welding.

Hydraulic hose is graded by pressure, temperature, and fluid compatibility. Hoses are used when pipes or tubes can not be used, usually to provide flexibility for machine operation or maintenance. The hose is built up with rubber and steel layers. A rubber interior is surrounded by multiple layers of woven wire and rubber. The exterior is designed for abrasion resistance. The bend radius of hydraulic hose is carefully designed into the machine, since hose failures can be deadly, and violating the hose's minimum bend radius will cause failure. Hydraulic hoses generally have steel fittings swaged on the ends. The weakest part of the high pressure hose is the connection of the hose to the fitting. Another disadvantage of hoses is the shorter life of rubber which requires periodic replacement, usually at five to seven year intervals.

文章出处：《机械制造专业英语》 主编：章跃 节选自第21课机器人

工业机器人是在生产环境中用以提高生产效率的工具，它能做常规乏味的装配线工作，或能做那些对于工人来说是危险的工作，例如：第一代工业机器人是用来在核电站中更换核燃料棒，如果人去做这项工作，将会遭受有害射线的辐射。工业机器人亦能工作在装配线上将小元件装配到一起，如将电子元件安放在电路印刷板，这样，工人就能从这项乏味的常规工作中解放出来。机器人也能按程序要求用来拆除炸弹，辅助残疾人，在社会的很多应用场合下履行职能。

机器人可以认为是将手臂末端的工具、传感器和手爪移动到程序指定位置的一种机器。当机器人到达位置后，它将执行某种任务。这些任务可以是焊接、密封、机器装料、拆装以及装配工作。除了编程以及系统的开停之外，一般来说这些工作可以在无人干预下完成。

如下叙述的是机器人系统基本术语：

1.机器人是一个可编程、多功能的机械手，通过给要完成的不同任务编制各种动作，它可以运动零件、材料、工具以及特殊装置。这个基本定义引导出后续段落的其他定义，从而描绘出一个完整的机器人系统。

2.预编程位置点是机器人为完成工作而必须跟踪的轨迹。在某些位置点上机器人将停下来做某些操作，如装配零件、喷涂油漆或者焊接。这些预编程点贮存在机器人的贮存器中，并为后续的连续操作所调用，而且这些预编程点像其他程序数据一样，可在日后随工作需要而变化。因且，正是这种可编程的特征，一个工业机器人很像一台计算机，数据可以在这里储存、后续调用与编辑。

3.机械手是机器人的手臂，它使机器人能弯屈、延伸和旋转，提供这些运动的是机械手的轴，亦是所谓的机械手的自由度。一个机械人能有3-16轴，自由度一词总是与机器人轴数相关。

4.工具和手爪不是机器人自身组成部分，但它们是安装在机器人手臂末端的附件。这些连在机器人手臂末端的附件可使机器人抬起工件、点焊、刷漆、电焊弧、钻孔、打毛刺以及根据机器人的要求去做各种各样的工作。

5.机器人系统还可以控制机器人的工作单元，工作单元是机器人执行任务所处的整体环境，该单元包括控制器、机械手、工作平台、安全保护装置或者传输装置。所有这些为保证机器人完成自己任务而必需的装置都包括在这一工作单元中。另外，来自外设的信号与机器人何时装配工作、取工件或放工件到传输装置上。

机器人系统有三个基本不见：机械手、控制器和动力源。

A．机械手

机械手做机器人系统中粗重工作，它包括两个部分：机构和附件,机械手也有联接附件基座，如下图所示一机器人基座与附件之间的联接情况。

机械手基座通常固定在工作区域的地基上，有时基座也可以移动，在这种情况下基座安装在导轨或者轨道上，允许机械手从一个位置移动到另外一个位置。

正如前面所提到的那样，附件从机器人基座上延伸出来，附件就是

机器人的手臂，它可以是直线型，也可以是轴节型手臂，轴节型手臂也是大家所知的关节型手臂。

机械臂使机械手产生各轴的运动。这些轴连在一个安装基座上，然后再练到托架上，托架确保机械手停留在某一位置。

在手臂的末端上，连接着手腕，手腕由辅助轴和手腕凸缘组成，手腕是让机器人用户在手腕凸缘上安装不同工具来做不同种工作。

机器手的轴使机械手在某一区域内执行任务，我们将这个区域为机器人的工作单元，该区域的大小与机械手的尺寸相对应，一个典型装配机器人的工作单元。随着机器人机械结构尺寸的增加，工作单元的范围也必须相应增加。

机械手的运动由执行元件或驱动系统来控制。执行元件或驱动系统允许各轴在工作单元内运动。驱动系统可用电气液压和气压动力，驱动系统所产生的动力经机构转变为机械能，驱动系统与机械传[FS:PAGE]动链相匹配。由链、齿轮和滚珠丝杠组成的机械传动链驱动着机器人的各轴。

B.控制器

机器人控制器是工作单元的核心。控制器储存着预编程序供后续条用、控制外设，及与厂内计算机进行通讯以满足产品经常更新的需要。

控制器用于控制机械手运动和在工作单元内控制机器人外设。用户可通过手持的示教盒将机械手运动的程序编入控制器。这些信息储存在控制器的存储器中以备后续调用，控制器存储了机器人系统的所有编程数据，它能存储几个不同的程序，并且所有这些程序均能编辑。

控制器要求能够在工作单元内与外设进行通信。例如控制器有一个输入端，它能标识某个机加工操作何时完成。当该加工循环完成后，输入端接通，告诉控制器定位机械手以便能抓取以加工工件，随后机械手抓取一未加工工件，将其放置在机床上。接着，控制器给机床开始加工的信号。

控制器可以由根据时间顺序而步进的机械式轮毂组成，这种类型的控制器可用在非常简单的机械系统中。用于大多数机器人系统中的控制器代表现代电子学的水平，是更复杂的装置，即它们是由微处理器操纵的。这些微处理器可以是8位，16位或32位处理器。它们可以使得控制器在操作工程中显得非常柔性。

控制器能通过通信线发送电信号，使它能与机器手各轴交流信息，在机器人的机械手和控制器之间的双向交流信息可以保持系统操作和位置经常更新，控制器亦能控制安装在机器人手腕上的任何工具。

控制器也有与厂内各计算机进行通信的任务，这种通信联系使机器人成为计算机辅助制造（CAM）系统的一个组成部分。

存储器。基于微处理器的系统运行时要与固态的存储装置相连,这些存储装置可以是磁泡，随机存储器、软盘、磁带等。每种记忆存储装置均能贮存、编辑信息以备后续调用和编辑。

C.动力源

动力源是给机器人和机器手提供动力的单元。传给机器人系统的动力源有两种，一种是用于控制器的交流电，另一种是用于驱动机械手各轴的动力源，例如，如果机器人的机械手是由液压和气压驱动的，控制信号便传送到这些装置中，驱动机器人运动。

对于每一个机器人系统，动力是用来操纵机械手的。这些动力可来源于液压动力源、气压动力源或电源，这些能源是机器人工作单元整体的一部分。

Robots

The industrial robot is used in the manufacturing environment to increase productivity . It can be used to do routine and tedious assembly line jobs , or it can perform jobs that might be hazardous to do routine and tedious assembly line jobs , or it can perform jobs that might be hazardous to the human worker . For example , one of the first industrial robots was used to replace the nuclear fuel rods in nuclear power plants . A human doing this job might be exposed to harmful amounts of radiation . The industrial robot can also operate on the assembly line , putting together small components , such as placing electronic components on a printed circuit board . Thus , the human worker can be relieved of the routine operation of this tedious task . Robots can also be programmed to defuse bombs , to serve the handicapped , and to perform functions in numerous applications in our society .

The robot can be thought of as a machine that will move an end-of-arm tool , sensor , and gripper to a preprogrammed location . When the robot arrives at this location , it will perform some sort of task . This task could be welding , sealing , machine loading , machine unloading , or a host of assembly jo[FS:PAGE]bs . Generally , this work can be accomplished without the involvement of a human being , except for programming and for turning the system on and off .

The basic terminology of robotic systems is introduced in the following :

1. A robot is a reprogrammable , multifunctional manipulator designed to move parts , materials , tools , or special devices through variable programmed motions for the performance of a variety of different task . This basic definition leads to other definitions , presented in the following paragraphs , that give a complete picture of a robotic system . 

2. Preprogrammed locations are paths that the robot must follow to accomplish work . At some of these locations , the robot will stop and perform some operation , such as assembly of parts , spray painting , or welding . These preprogrammed locations are stored in the robot’s memory and are recalled later for continuous operation . Furthermore , these preprogrammed locations , as well as other program data , can be changed later as the work requirements change . Thus , with regard to this programming feature , an industrial robot is very much like a computer , where data can be stored and later recalled and edited .

3. The manipulator is the arm of the robot . It allows the robot to bend , reach , and twist . This movement is provided by the manipulator’s axes , also called the degrees of freedom of the robot . A robot can have from 3 to 16 axes . The term degrees of freedom of freedom will always relate to the number of axes found on a robot .

4. The tooling and grippers are not part of the robotic system itself ; rather , they are attachments that fit on the end of the robot’s arm . These attachments connected to the end of the robot’s arm allow the robot to lift parts , spot-weld , paint , arc-weld , drill , deburr , and do a variety of tasks , depending on what is required of the robot .

5. The robotic system can also control the work cell of the operating robot . the work cell of the robot is the total environment in which the robot must perform its task . Included within this cell may be the controller , the robot manipulator , a work table , safety features , or a conveyor . All the equipment that is required in order for the robot to do its job is included in the work cell . In addition , signals from outside devices can communicate with the robot in order to tell the robot when it should assemble parts , pick up parts , or unload parts to a conveyor .

The robotic system has three basic components : the manipulator , the controller , and the power source .

A . Manipulator

The manipulator , which does the physical work of the robotic system , consists of two sections : the mechanical section and the attached appendage .  The manipulator also has a base to which the appendages are attached . Fig.1 illustrates the connection of the base and the appendage of a robot .

The base of the manipulator is usually fixed to the floor of the work area .[FS:PAGE] Sometimes , though , the base may be movable . In this case , the base is attached to either a rail or a track , allowing the manipulator to be moved from one location to another .

As mentioned previously , the appendage extends from the base of the robot . The appendage is the arm of the robot . It can be either a straight , movable arm or a jointed arm . the jointed arm is also known as an articulated arm .

The appendages of the robot manipulator give the manipulator its various axes of motion . These axes are attached to a fixed base , which , in turn , is secured to a mounting . This mounting ensures that the manipulator will remain in one location。

At the end of the arm , a wrist  is connected . The wrist is made up of additional axes and a wrist flange . The wrist flange allows the robot user to connect different tooling to the wrist for different jobs .

The manipulator’s axes allow it to perform work within a certain area . This area is called the work cell of the robot , and its size corresponds to the size of the manipulator . Fig.2 illustrates the work cell of a typical assembly robot . As the robot’s physical size increases , the size of the work cell must also increase .

The movement of the manipulator is controlled by actuators , or drive systems . The actuators , or drive system , allows the various axes to move within the work cell . The drive system can use electric , hydraulic , or pneumatic power . The energy developed by the drive system is converted to mechanical power by various mechanical drive systems .The drive systems are coupled through mechanical linkages .These linkages, in turn , drive the different axes of the robot . The mechanical linkages may be composed of chains , gears ,and ball screws.

B. Controller

The controller in the robotic system is the heart of the operation. The controller stores preprogrammed information for later recall, control peripheral devices, and communicates with computers within the plant for constant updates in production

The controllers is used to control the robot manipulator’s movements as well as to control peripheral components within the work cell. The user can program the movements of the manipulator into the controller through the use of a hand-held teach pendent. This information is stored in the memory of the controller for later recall. The controller stores all program data of the robotic system. It can store several different programs, and any of these programs can be edited.

The controller is also required to communicate with peripheral equipment within the work cell. For example, the controller has an input line that identifies when a machining operation is completed. When the machine cycle is completed, the input line turns on, telling the controller to position the manipulator so that it can pick up the finished part. Then, a new part is picked up by the manipulator and placed into the machine. Next, the controller signals the machine to start operation.[FS:PAGE]

The controller can be made from mechanically operated drums that step through a sequence of events. This type of controller operates with a very simple robotic system. The controllers found on the majority of robotic systems are more complex devices and represent state-of-the-art electronics. That is, they are microprocessor-operated. These microprocessors are either 8-bit, 16-bit, or 32-bit processors. This power allows the controller to be very flexible in its operation.

The controller can send electric signals over communication lines that allow it to talk with the various axes of manipulator. This two-way communication between the robot manipulator and the controller maintains a constant update of the location and the operation of the system. The controller also controls any tooling placed on the end of the robot’s wrist.

The controller also has the job of communicating with the different plant computers . The communication link establishes the robot as part of a computer-assisted manufacturing (CAM) system.

As the basic definition stated , the robot is a reprogrammable , multifunctional manipulator . Therefore , the controller must contain some type of memory storage . The microprocessor-based systems operate in conjunction with solid-state memory devices . These memory devices may be magnetic bubbles , random-access memory , floppy disks , or magnetic tape . Each memory storage device stores program information for later recall or for editing .

C. Power supply

The power supply is the unit that supplies power to the controller and the manipulator . Two types of power are delivered to the robotic system . One type of power is the AC power for operation of the controller . The other type of power is used for driving the various axes of the manipulator . For example , if the robot manipulator id controlled by hydraulic or pneumatic manipulator drives , control signals are sent to these devices , causing motion of the robot .

For each robotic system , power is required to operate the manipulator . This power can be developed from either a hydraulic power source , a pneumatic power source , or an electric power source , These power sources are part of the total components of the robotic work cell .

1 Definition

The diameters, threads per inch (TPI) and thread pitch, etc. are necessary to completely identify a thread. In a shop, specialty gauges are required to accurately gauge or identify threads. In the field, in the absence of these gauges, thread "leaf" gauges can be used to identify the "Threads Per Inch" (TPI) and the thread pitch. On threads you have determined to be straight threads, a caliper can be used to measure the "Outside Diameter of the Male" (ODM) or the "Inside Diameter of the Female" (IDF). A caliper can also be used to take measurements of tapered thread diameters. However, these are more difficult to define because of the taper. Fortunately, there are few tapered threads to deal with and these can usually be identified from the nominal ODM and the TPI.

However, identifying the thread may not fully identify what is needed in a mating fitting. The application is the primary limiting factor on the thread type used. We offer products with a wide variety of threads used with hose, pipe and hydraulics.

When attempting to choose a fitting, it is always advisable to first identify the thread to which it must connect. This may entail checking with a fitting or equipment manufacturer.

The fire hose thread specifications for some local municipal fire equipment and hydrants may vary according to local specifications. These can generally be most easily identified by contacting the local fire department responsible for the hydrant. The most common thread used on fire equipment is National Standard Thread (NST), also known as National Hose thread (NH).

When it is not possible to identify the thread:

1) Determine the number of threads per inch by measuring the distance from peak of thread to peak of thread across the largest number of whole threads. Then divide the number of threads by the measurement. (This will provide the TPI).

2) Check to see if the thread is straight or tapered.

a) Straight Threads

Measure the "Outside Diameter of the Male" (ODM) or the "Inside Diameter of the Female" (IDF), from peak of thread to peak of thread.

b) Tapered Threads

Measure the "Outside Diameter of the Male" (ODM) at the large end and the small end, or the "Inside Diameter of the Female" (IDF) at the large end and the small end, from peak of thread to peak of thread. Then measure the Outside Diameter (OD) of the unthreaded pipe.

Once the application and these two pieces of information have been determined, the thread can generally be determined. When in doubt, contact the manufacturer.

Threading Information

Thread Dimensions

Nominal Dimensions of Standard Threads

NOTE: Female NPT (Tapered Pipe) thread is not available on hose swivel nuts.

Normal Engagement Length

of NPT Thread in Inches ("A") *

Thread Sealing Tips

More Thread Sealing Tips...

Sealing NPT threads can be an exasperating experience if certain techniques are not followed. The following tips will help alleviate many common problems in thread sealing:

1. Always use some type of sealant (tape or paste) and apply sealant to male thread only. If using a hydraulic sealant, allow sufficient curing time before system is pressurized.

2. When using tape sealant, wrap the threads in a clockwise motion starting at the first thread and, as layers are applied, work towards the imperfect (vanishing) thread. If the system that the connection being made to cannot tolerate foreign matter (i.e. air systems), leave the first thread exposed and apply the tape sealant as outlined above.

3. When using paste sealant, apply to threads with a brush, using the brush to work the sealant into the threads. Apply enough sealant to fill in all the threads all the way around.

4. When connecting one stainless steel part to another stainless steel part that will require future disassembly, use a thread sealant that is designed for stainless steel. This stainless steel thread sealant is also useful when connecting aluminum to aluminum that needs to be disconnected in the future. These two materials gall easily, and if the correct sealant is not used, it can be next to impossible to disassemble.

5. When connecting parts made of dissimilar metals (i.e. steel & aluminum), standard tape or paste sealant usually performs satisfactorily.

6. For sizes 2" and below, tape or paste usually performs satisfactorily. When using thread tape, four wraps (covering all necessary threads) is usually sufficient.

7. For sizes 2-½" and above, thread paste is recommended. If thread tape is used, eight wraps (covering all necessary threads) is usually sufficient. Apply more wraps if necessary.

8. For stubborn to seal threads, apply a normal coating of thread paste followed by a normal layer of thread tape.

9. For extremely stubbo[FS:PAGE]rn to seal threads, apply a normal coating of thread paste followed by a single layer of gauze bandage followed by a normal layer of thread tape.

Caution!

When this procedure is done, the connection becomes permanent. Extreme measures will be necessary to disconnect these components. All other measures to seal the threads should be explored prior to the use of this technique.

10. Over-tightening threads can be just as detrimental as insufficient tightening. For sizes 2" and below, hand tighten the components and, with a wrench, tighten 3 full turns. for sizes 2-½" and above, hand tighten the components and, with a wrench, tighten 2 full turns.

2 Pipe Thread Standards

Two common pipe thread standards exist:

National Pipe Thread (NPT) - a tapered thread

National Standard Free-Fitting Straight Mechanical Pipe Thread (NPSM) - a straight thread

Less common standards also exist:

Garden Hose Thread (GHT)

Fire Hose Coupling (NST)

British Standard Taper Pipe Thread (BSPT)

Female NPT threads can be designated as "FPT" and male NPT threads can be designated as "MPT." I have also seen female NPT threads designated as "FNPT" and male as "MNPT".

Straight Versus Tapered Threads

Threaded pipe can be connected to join things together, which does not necessarily produce a leakproof seal, or they can be joined and sealed.

Straight threads only provide a mechanical junction. They don't really seal.

Tapered threads both join and seal. The deeper you drive them, the tighter the seal.

Pipe Thread Tape

Whenever you want a good seal when screwing together pipes and fittings, use pipe thread tape. This is usually made of PTFE, the most famous brand of which is Teflon.

In addition to sealing, pipe thread tape also lubricates the joint, which:

makes it easier to tighten it

makes it easier to disassemble the joint in the future

reduces/eliminates thread galling [Thread galling is when threads weld themselves together. This is more common with pipes and fasteners made from alloys that protect themselves from corrosion by developing their own oxide surface film, like aluminum and stainless steel.

Standard Pipe Sizes

Pipe sizes do not refer to any physical dimension of modern pipe. If you measure a piece of 1/4" NPT pipe, you will have a hard time finding anything there that measures 1/4".

Historical note:

The sizes derive from the days when pipes were made of iron, pipe walls were rather thick, and the internal diameter (ID) was standardized. At that time, if you specified a 1/2" pipe, it had an internal diameter of 1/2", and an outer diameter that depended on the thickness of the wall.

Nowadays, the standards measure the threaded part of the pipe, the outer diameter (OD). This lets thin-wall and thick-wall pipe use the same fittings.

But we kept the same names, so when you say 1/2" pipe, you get a pipe whose outer diameter is the same as that of an old-fashioned iron pipe whose inner diameter was 1/2".

In order [FS:PAGE]to get the right size, you should measure the outer diameter (OD) of the pipe, and look it up in a table to find out what it is officially called. It's also a good idea to measure the threads per inch (TPI). The combination of OD and TPI provide positive identification of standard pipe sizes.

the function of a manufacturing engineer is ,therefore ,to determine and define the equipment ,tools ,and processes required to convert the design of the desired product into reality ni an efficient manner .In other words ,it is the engineer's task to find out the most appropriate ,optimal combination of machinery ,materials ,and methods needed to achieve economical and trouble-free production.Thus ,a manufacturing engineer must have a strong background in materials and up-to-date machinery as well as the ability to develop analytical solusions and alternatives for the open-ended problems expreienced in manufacturing .This is in addition to having a sound knowledge of the theoretical and practical aspects of the various manufacturing methods.

Efficient in production

since the first use of machine tools ,there has been a gradual trend toward making machines more ifficient by combining operations and by transferring more skill to the machine,thus ruducing time and labor.To meet those needs,machine tools have become complex both in disign and some are completely automatic .This technical development has made it possible to attain the high production rate with row labor cost that is essential for any society wishing to enjoy high living standards.Computer-aided design and manufacturing are significant steps of progress.

Along with the development of production machines ,the quality in manufacturing must be maintained.Quality and accuracy in manufacturing operations demend that dimensional control be maintained to provide parts that are interchangeable and give the best operating service.For mass production,any one of a quality of parts is quickly assembly.A product made of interchangeable parts is quickly assembled,lower in cost ,and easily serviced.To,maintain this dimensional control ,appropriate inspection facilities must be provided.

Three criteria that determine economical production are;

one,A functional but simple design that has appropriate aesthetic quality.

two,A material choice that represents the best compromise among physical proterties,appearance,cost ,and workability or machinability.

Three,selection of the manufacturing processes that will yield a product with no more accuracy or better surface finish than necessary and at the lowest possible unit cost.

Porduct Engineering and Design

It is important that the product be designed with material,manufacturing ,and engineering to be competitive.For any manufactured product it is possible to specify a stronger,a more corrosion-resistant,or a longer life material,for example ,but it is the engineer's obligation not to overlook the opportunity of economical production.This leads to value engineering ,which is the substitution of cheaper materials or elimination of costly materials or of unnecessary operations.

To produce parts of greater accuracy ,more expensive machine tools and opreations are necessary,more highly skilled labor is required ,and rejected parts may be more numerous.Products should not be designed with greater accuracy than the s[FS:PAGE]ervice requirements demends.A good design incensed consideration of a finishing or coating operation,because a product is often judged for apperance as well as function and operation.Many productions,such as those made from colored plastics or other special materials,are more saleable because of appearance.In most cases the function of the part is the deciding factor.This is particulary ture where great strength,wear ,corrosion,resistance,or weight limitations are encountde.

For mass produced parts the design should be adaptable to mass production-type machines with a minimum of different setups .Whenever a part is loaded ,stored ,and reloaded into another machine,costs are involved that may not add value to the product.

On the other hand,we can make steel harder by rapid cooling .We heat it up beyond the critical temperature ,and then quench it in the water or some other liquid.The rapid temperature drop fixes the structural changes in the steel ,which occurred at the critical temperature ,and makes it very hard.But a bar of this hardened steel is more liable to fracture than normal steel.We therefore heat it again to a temperature below the critical temperature ,and cool it slowly.This treatment is called tempering .It helps to relieve the internal stresses ,and maks the steel less brittle than before.The properties of tempered steel enable us to use it in the manufacture of tools ,which need a fairly hard steel.High carbon steel is harder than tempered steel ,but it is much more difficult to work.

These heat treatments take place during the various shaping operations.We can obtain bars and sheets of steel by rolling the metal through huge rolls in a rolling mill.The roll presures must be much greater for cold rolling than for hot rolling ,but cold rolling enables the operators to produce rolls of great accuracy and uniformity,and with a better surface finish.Other shaping operations include drawing into wire,casting in moulds,and forging.

The mechanical working  of metal is the shaping of metal in either a cold or a hot state by some mechanical means.This does not include the shaping of metal by machining or grinding,in which process metal is actually machined off,nor does it include the casting of molten metal into some form by use of molds.In mechanical working process,the metal is shaped by pressured-acutely forging,bending ,squeezing,drawing ,or shearing it to its final shape.In thest processes the metal may be either cold or hot worked .Ahthough normal roon temperatures are ordinarily used for cold working of steel,temperatures up to the recrystalization ran[FS:PAGE]ge are sometimes used.Hot working of metals takes place above the recrystalization or work -hardening range.For steel,recrystslization starts around 650 to 700,although most hot work on steel is done at temperatures considerably above this range .There is no tendency for hardenning by mechanical work until the lower limit of the low recrystalization range is reached.Some metals,such as lead and tin,have a low recrystslline range and can be hot-worked at room temperature,but  most commercial metals raquire some heating .Alloy composition has a great influence upon the proper working range ,the ususl result being to raise the recrytalline range temperature .This range may also be increased by prior cold working.

Figure 1. Locations of Mechanical Test Samples

Locations 1 and 2 are in the runners; location 3 is in the casting near the main gate; location 6 is in the casting about 160 mm (6.3 inch) from the main gate; and location 7 is in the casting near the overflows  and about 240 mm (9.4 inch) from the main gate. Locations 3, 6 and 7 have similar cross section areas and uniform thicknesses. Samples were cut from locations 3, 6 and 7 and machined as uniaxial tensile or fatigue samples with dimensions shown Figure 2.

Figure 2. Dimensions of the Mechanical Test Samples from Locations 3, 6 and 7

The dimensions of the tensile and fatigue samples were selected consistent with the recommended dimensions set forth in ASTM Standard for Tensile of Metallic Materials E-8. The normal thickness of the tensile and fatigue samples was 2.9 mm (0.114 inch)

After machining, selected samples were visually examined and subjected to X-ray radiography to assess their porosity and related defect occurrence. The number of machined samples rejected by x-ray and/or visual examination was listed in Table 1.

Table 1: Number and Percent Samples Rejected from Locations 3, 6, and 7.

As indicated in Table 1, the samples die cast with shot delays of 0.5 and 6.5 seconds were essentially free of massive porosity and cold shuts, while the samples die cast with delays of 13 seconds contained relatively large fraction of rejected samples due to porosity, cold shuts, and misruns.

Tensile Results:

Room temperature tensile tests were performed on samples which passed the visual and X-ray radiography screening procedures. The tensile tests were conducted using an Instron 1322 test frame with a cross head velocity of 8 x 10^-4 inches per second. Eight or more tensile tests were conducted on samples from Location 7 for each of the die casting conditions studied. The average stress at fracture (also taken as the ult[FS:PAGE]imate tensile strength) and the fracture strain for the tested samples from Location 7 are presented in Table 2 for the six die casting conditions studied (three shot delay times and two amount of plunger lubricant). The tensile values for separately die cast circular cross section test bars of the same alloy reported by Briggs & Stratton Corporation and the North American Die Casting Association (NADCA) Specifications values for alloy 383 are also presented in Table 2 for comparison.

Table 2: Tensile Data for Samples from Location 7

As the mechanical properties for these limited ductility samples may not be adequately described with a “normal” or Gaussian distribution, the mechanical property data were also analyzed using a two-parameter Weibull distribution. The Weibull distribution results for the Location 7 samples and separately die cast 0.25 inch diameter test bars are given in Table 3.

Table 3: Weibull Distribution Data for Tensile Properties for Location 7 Samples

The tensile data in Tables 2 and 3 indicate no statistically significant difference between the 0.5 and 6.5 second shot delay conditions. The tensile fracture st[FS:PAGE]ress and fracture strains are significantly reduced with the 13 second shot delay time condition. There is no significant effect of the two levels of plunger lubricant at any given shot delay time condition. The tensile stress and fracture strain are greater for the die cast 0.25 inch diameter tensile samples than for the rectangular cross section samples cut from the die castings. The tensile properties of the samples removed from the die casting are significantly less than the NADCA “handbook” values.

The smaller fracture stress and strain values associated with the 13 second shot delay condition are attributed to:

(1) an anticipated larger volume fraction of ESP

(2) an increased porosity level (decreased density)

(3) a greater oxide content, and

(4) an increased occurrence of “cold shuts”.

The difference in tensile properties is not attributed to any significant difference in sludge content.

 Fractrographic analysis of the tensile samples will be posted in the Fractrographic Analysis  section of this Web Page.

Fatigue Results:

Room temperature uniaxial fatigue tests were conducted using an Instron 1322 test frame. The maximum stress level was 12 ksi in all tests. The stress ratio, R, equaled 0.1. The testing frequency was 10 Hertz. Ten or more samples from both Locations 3 and 6 were tested for each die casting condition. The two-parameter Weibull distribution data for Samples from Locations 3 and 6 for the various die casting conditions are presented in Table 4.

Table 4: Weibull Data for Fatigue Results for Samples from Locations 3 and 6

The NADCA Specification value for the fatigue strength of 383 aluminum alloy is 21 ksi, which would suggest that the number of cycles before failure for the samples would be in excess of ten million at the stress level used (12 ksi). Only one sample for the 6.5 second shot delay and 1.3 gram plunger lubricant condition had not broken at 4 million cycles. As indicated in Table 4, the fifty percent average number of cycles to failure was 411,000 or less for all of the conditions tested for these two sample locations. With the exception of the Location 3, 13 second shot delay and 1.3 gram plunger lubricant condition, there does not appear to be [FS:PAGE]a significant difference in the fatigue life data for the other conditions. The lower number of cycles to failure for the 13 second shot delay samples is attributed primarily to the increased occurrence of cold shuts and surface flow lines observed for those samples.

Fractographic analyses of the fatigue samples will be posted in the Fractographic Analysis Section of this web page.

 The die casting selected for production during this campaign was a Model 19 base, identified as Briggs & Stratton Part # 212143.This casting is similar to the casting shown in Figure 1 of the Characterization Section of the project webpage (www.mse.eng.ohio-state.edu/~mobley/diecasting). The designed total shot weight (total quantity of alloy poured) was 5.25 pounds, and the designed resultant weight of the casting and overflows was 4.0 pounds. The die casting alloy was a modified 383 aluminum alloy of the composition given in Table 1.

The compositional data presented in Table 1 were obtained from optical emission spectrographic (OES) analyses of samples taken from the holding furnace during the period the campaign was conducted. Using the Aluminum Association density formula, the predicted theoretical density of an aluminum alloy of the composition given in Table 1 is 2.774 grams per cubic centimeter (0.10013 pounds/cubic inch).

A 900 ton Lester die casting machine (Briggs & Stratton Station 42) was used for this campaign. The setup machine conditions are listed in Table 2.

The primary objective of this campaign was to prepare die cast samples with var[FS:PAGE]ying amounts of ESP. Since the amount of ESP is anticipated to increase with increasing dwell time in the shot sleeve and greater heat transfer from the alloy to the shot sleeve, the two process variables selected as variables were shot delay time and amount of plunger lubricant applied to the shot sleeve. After ten shots were made to allow the shot sleeve and die to reach the quasi-steady state thermal condition, 193 die castings were made with selected shot delay times and amounts of applied plunger lubricant. Castings were produced for each of the experimental conditions given in Table 3.

The remainder of the castings (55) were produced during transitions between the groups listed in Table 3 and during special production conditions before and after the above groups were made. The special production conditions included parts made with 15 second shot delay times and interrupted pour experiments. All of the castings produced as part of the listing given in Table 3 were made after the die and shot sleeve had reached the quasi-steady state thermal condition and with all of the other independent process variables held constant. All of the castings made during the Table 3 groupings were complete (i.e., the runners, castings, and overflows were filled) and the B&S die casting machine operator indicated that these parts were visually acceptable for forwarding for machining and additional testing (X-ray and/or pressure).

The average, standard deviation, and fractional variance (standard deviation divided by the average) values for a number of recorded process variables during the production of each of the controlled groups listed in Table 3 are given in Table 4.

The average biscuit lengths based on the recorded values on the die casting machine shot profile system were about 2 inches, which were larger than the setup values  (1.0 and 1.5 inches). The fractional variances for the recorded biscuit lengths were all about 5%. The recorded cycle times varied in keeping with the imposed shot delay times.  The cycle times for the 6.5, 13, and 14 second shot delay shots are about 6, 12.5, and 13.5 seconds longer, respectively, than the cycle time for the 0.5 second delay time shots. The observed variation of increasing squeeze distance with increasing shot delay time and increasing amount of plunger lubricant is unexpected and no explanation for this observance is available at this time.

The slow shot velocities are essentially constant (at 7.83 inches/second) for all of the conditions imposed throughout this experimental campaign. The setup fast shot velocity for the 0.5 second shot delay case was to be between 105 and 125 inches/second. The recorded fast shot velocities were around 105.7 inches per second for the 0.5 second shot delay time condition, but decreased with increasing shot delay times. Both the reduction of fast shot velocity and the increased squeeze distances with increasing shot delay times and amounts of plunger lubricant suggest that these two process variables are dependent on the amount of ESP present in the system, and, in turn, the viscosity of the liquid-solid mix being pushed through the gate(s).

The die castings prepared during the Briggs and Stratton June 5th campaign will be sectioned to determine the densities of each section (biscuit, runners, castings, and overflows) and the effects of shot delay time and amount of plunger lubricant applied will be analyzed on the porosity distributions and mechanical proterties. The samples will then be metallographically characterized to assess the amount of externally solidified phase present as a function of the die casting conditions and affect the mechanical properties of the die castings.

Figure 1. The top-view of the A383 complete casting

Representative examples of the ESP as found in the runner in front of the main gate and in the casting are shown in optical photomicrographs of Figures 2 and 3, respectively. Figures 2 and 3 are views at relatively low magnifications. The variation in number and size of the ESP as a function of distance from the gate in the runner and casting are shown in Figure 4. The ESP regions are generally larger in the runner than within the casting and the number per unit cross-sectional area is less in the runner than in the casting.

Figure 2: ESP in Runner in Front of Main Gate

Figure 3: ESP in Body of Casting

Figure 4: The area fraction and number per unit area of ESP as a function of distance from the gate

Medium magnification optical photomicrographs of an ESP region in the runner are shown in Figure 5 (Region A identified in Figure 2, straight edge) and Figure 6 (Region B identified in Figure 2, rough edge). As noted in Reference 3 and 4, the morphology of the silicon in the eutectic product varies spacially within the various regions (ESP versus non-ESP regions) as well as within the ESP particles.

Figure 5: Microstructure of ESP in the runner (region A in Figure 2 near straight edge)

Figure 6: Microstructure of ESP in the runner (region B in Figure 2 near rough edge)

Figures 7 and 8 are optical photomicrographs which show typical microstructures of the ESP regions found within the casting. Both photomicrographs were taken of regions shown in Figure 3.  Figure 7 shows the microstructure of the ESP Region C in Figure 3 near the straight edge of that particle. Figure 8 shows the microstructure of the ESP Region D in Figure 3 near the rough edge of that region. As with the ESP regions in the runner section of the system, the silicon morphologies in the ESP regions in the casting vary spacially.

Figure 7: Microstructure of ESP in the casting (region C in Figure 3)

Figure 8: Microstructure of ESP in the casting (region D in Figure 3)

Representative optical photomicrographs with same magnification of neighboring non-ESP or matrix (alloy solidified within the cavity) found in the casting (Region E in the Figure 3) is shown in Figure 9. Compared with Figure 7 and Figure 8, the phases present in both the ESP and alloy solidified [FS:PAGE]within the casting cavity are the same. However, the observed area fraction of primary alpha-aluminum and Al-Si eutectic differ in the neighboring ESP and non-ESP regions. Generally, the observed area fraction of primary alpha-aluminum is greater in the ESP regions than the alloy solidified within the die cavity.

Figure 9: Microstructure of non-ESP (matrix) region in the casting (region E in Figure 4)0

In the runner section of the casting, the interface between the ESP and non-ESP regions frequently contain pores and cracks as shown in Figure 10.

Figure 10: Optical Photomicrograph of Non-ESP/ESP Interface in Runner Section  Exhibiting Pores and Cracks

The interface between the ESP and non-ESP regions in the casting section do not generally exhibit as pronounced pores or cracks as in the runner. A typical Non-ESP/ESP interface within the casting section is shown in Figure 11.

Figure 11: Optical Photomicrograph of Non-ESP/ESP Interface in the Casting

Higher magnification micrographs (taken with a scanning electron microscope (SEM)) of the Non-ESP/ESP interfaces within the casting indicate that voids occur along this interface, as shown in Figures 12a through 12d.

a

b

c

d

Figure 12: SEM Micrograph of Non-ESP/ESP Straight Interface within the Casting

References Relating to ESP/Cold Flakes in Die Castings:

The following references provide descriptions of the formation mechanisms, general appearance, and effects of ESP on die cast products:

1.  Paul Paliani, Lawrence Zalewski, Joel Barreto, Nao Tsumagari, Jerald Brevick, and Carroll Mobley, "Alloy Cooling and Solidification in Horizontal Cold Chamber Die Casting Shot Sleeves", Transactions 18th International Die Casting Congress & Exposition, North American Die Casting Association, 1995, 149-155.

2.  N. Tsumagari, J.R.Brevick, C.E.Mobley, "Control of Microstructures in Aluminum Alloy Diecastings", AFS Transactions, 127, 1998, 15-20.

3.  Toru Komazaki and Naomi Nishi, "Effects of Silicon Contents in Formation of Anomalous Structures of Aluminum Alloy Die Castings", Transactions 19th International Die Casting Congress & Exposition, North American Die Casting Association, 1997, 191-194.

4.  M. Gershenzon, P.W.Rohan and M.T.Murray, "Formation of Cold Flakes in Aluminum High Pressure Die Casting", Transactions 20th International Die Casting Congress & Exposition, North American Die Casting Association, 1999, 305-315.

5. Walkington, W., " Die Casting Defects: Causes and Solutions, Chapter Twenty-Two, Cold Flakes", NADCA, 1997, 155- 158.

There are two purposes for conducting these simulations; (1) to determine the flow pattern and wave formations of liquid alloy in shot sleeves to reduce air entrapment, and (2) to predict the amount of externally solidified product (ESP) formed and carried into castings. Air entrapment in liquid alloy during the slow shot portion of the process increases the gas porosity of the die casting and thereby degrades its quality. The ESP also degrades the quality of die cast product. Coupled fluid flow and solidification models will provide insight to the preferred plunger displacement history which produce the desired wave dynamics and amount and distribution of solidified phases to minimize air entrapment and ESP in the die cast products.

2. Description of the cold chamber die casting process

Die casting is characterized by a source of hydraulic energy that imparts high velocity to molten metal to provide rapid filling of a metal die. After molten metal is introduced into shot sleeve, the plunger moves along the shot sleeve and pushes the liquid alloy through the shot sleeve and into the runner and casting cavity. During the first stage of the plunger motion, the plunger velocity is relatively low. After the plunger has moved a given distance, it is accelerated to a higher velocity for filling the runner and casting cavity. The first portion of the plunger history is called the slow shot, and the latter, the fast shot. Molten metal is injected into die cavity during the fast shot. The emphasis of the simulations in this program are for the shot sleeve filling period and the slow shot portion of the process, as these are the periods when wave and ESP formations are most prevalent.

Reference Related to Shot Sleeve Fluid Flow Phenomena:

The following references relating to fluid flow studies and phenomena are provided:

1. Marilyn Thome. and Jerald R. Brevick, "Optimal Slow Shot Velocity Profiles For Cold Chamber Die Casting", North American Die Casting Association, October 2-5, 1995, 53-59

2. Lester W. Garber, "Filling of the Cold Chamber during Slow-Shot Travel," Die Casting Engineer, July-August 1981, 36-38

3. Lester W. Garber, "Theoretical Analysis and Experimental Observation of Air Entrapment during Cold Chamber Filling," Die Casting Engineer, May-June 1982, 14-22

4. H.Y. Lu, W.B. Lee, "A Simplified Approach for the Simulation of Metal Flow in a cylindrical Sleeve Diecasting Cavity," Journal of Materials Processing Technology 91, 1999, 116-120

5. J.H. Jeong, and D.Y. Yang, "Finite Element Analysis of Transient Fluid Flow with Free Surface Using VOF (Volume-Of-Fluid) Method and Adaptive Grid," International Journal for Numerical Methods in Fluids, Vol. 29, 1999, 657-684

6. J. Lopez, J. Hernandez, F. Faura, G. Trapaga, "Shot Sleeve Wave Dynamics in the Slow Phase of Die Casting Injection," Journal of Fluids Engineering, Vol. 122, 2000, 349-356

7. Gerald Backer, Frank Sant: "Using Finite Element Simulation f[FS:PAGE]or the Development of Shot Sleeve Velocity Profiles," North American Die Casting Association, 1997, 17-20

8. F. Faura, J. Lopez, J. Hernandez, “On the Optimum Plunger Acceleration Law in the Slow Shot Phase of Pressure Die Casting Machines,"  International Journal of Machine Tools & Manufacture, Vol. 41, 2001, 173-191

3. Modeling by FLOW3D

FLOW3D, a commercial package for fluid flow analyses, was used (1) to compute the flow pattern of various fluids (water, liquid aluminum, and other specified fluids) in shot sleeves, and (2) to predict the amount of ESP formed on the shot sleeve for various thermal conditions. Two geometric models were used, a 2-D model and a 3-D model. The 2-D model is a rectangular cross section channel and the 3-D model is a cylindrical cross section channel. Both models (2-D and 3-D) incorporate (a) filling of the shot sleeve to a specified percent fill with a given fill rate, and (b) movement of the plunger with a specified position-time (or velocity-position) history. Examples of the results from selected Flow3D simulations of the two models with water, liquid aluminum, or a high viscosity (10 centipoise) liquid are provided on this web page.

A. 2-D Model

a. Schematic view of geometry

* Without runner

* With runner

b. History of plunger movement

c. Results

- Coarse Mesh and laminar flow

* Filling Process

1. No surface tension, water, inlet velocity = -25cm/sec

2. Surface tension = 670 dyne/cm, aluminum, inlet velocity = -25cm/sec

This animation shows a typical flow pattern during filling. In this period, air can be entrapped into liquid metal. After filling, residual waves still remain, and the residual waves can affect wave pattern during plunger movement.

* The effect of plunger velocity

1. Plunger velocity = 30cm/s, water, acceleration time = 0.1 sec (very low plunger velocity)

2. Plunger velocity = 52.5cm/s, water, acceleration time = 0.1 sec

3. Plunger velocity = 55cm/s, water, acceleration time = 0.1 sec

4. Plunger velocity = 80cm/s, water, acceleration time = 0.1 sec ( very high plunger velocity)

For the above simulations, I have neglected the effect of surface tension, considered 50% filling of the shot sleeve, and taken water as the fluid by incorporating viscosity and density of water in the present simulation, and the acceleration time is taken to be 0.1 sec.

In case of 30cm/s plunger velocity, wave created can't reach top of the shot sleeve, and reflected waves entrap considerable amount of air.

In case of 52.5 cm/s plunger velocity, wave created entraps very small amount of air.

In case of 80 cm/s plunger velocity, wave created goes along the top surface of the shot sleeve and then comes down. Created wave entraps very much amount of air.

* The effect of plunger acceleration

1. Plunger velocity = 52.5cm/s, water, acceleration time = 0.1 sec

2. Plunger velocity = 52.5cm/s, water, acceleration time = 0.2 sec

3. Plunger velocity = 52.5cm/s, water, acceleration time = 0.3 sec

4. Plunger velocity = 52.5cm/s, water, acceleration time = 0.4 sec

5. Plunger velocity = 52.5cm/s, water, acceleration time = 0.6 sec

6. Plunger velocity = 52.5cm/s, water, acceleration time = 0.7 sec

For coarse mesh, the effect of plunger acceleration on the wave pattern is not consistent.

See the effect of plunger acceleration for the fine mesh.

* The effect of kinematic viscosity

water viscosity = .0114 poise, water density = 0.999 g/cm³

1. plunger velocity = 50, kinematic viscosity = 0.0114, Re = 4.38*10⁴

a. water viscosity and density

b. 10 times of water viscosity and density

c. 20 times of water viscosity and density

2. plunger velocity = 75, kinematic viscosity = 0.0171, Re = 4.38*10⁴

a. water viscosity and density = 0.666

b. water density and viscosity = 0.0171

These simulations show the effect of kinematic viscosity which is dynamic vicosity divided by density.

At the same velocity, although density and viscosity change, if kinematic viscosity is not changed, the wave patterns are nearly identical.

Although Re number is the same, if plunger velocities are different, wave patterns are also different.

* The effect of surface tension

plunger velocity = 80 cm/sec, aluminum, acceleration time = 0.1 sec

1. No surface tension

2. Surface tension = 670 dyne/cm

3. Surface tension = 3000 dyne/cm

The first simulation shows the flow pattern without surface tension

and the others show the effect of surface tension. Two values of surface tension are used for flow simulations

In the second one, 670 dyne/cm is used, because this value represent the surface tension of Al in a reducing gas environment, and In the last one, 3000 dyne/cm, because this value represents the surface tension of Al when an oxide layer gets formed on the surface.

As surface tension value increases, the wave created tend to come down to reduce the surface area.

* Experiment vs. Simulation- Effect of mesh size and turbulence on the predicted results 

Experiment vs. Simulation

2in Diameter,and 20in length shot sleeve

1. 30%fill, plunger velocity = 25.4 in/sec (64.5 cm/sec), acceleration = 2.25 in/sec/in

A. 3-D Experiment

B. 2-D Simulation

2. 70%fill, plunger velocity = 9.6 in/sec (24.4 cm/sec), acceleration = 3.0 in/sec/in

A. 3-D Experiment

B. 2-D simulation

2-D simulations are compared with 3-D experiments. This experiments were conducted at Dr. Brevick's lab. in industrial engineering department in 1993.

Wave patterns of these simulations agree with those of experiments.

Effect of mesh size and turbulence on the simulation results

Generally, the agreement between simulation and experimental results improve as the mesh size used in the simulations decreases. It is also frequently found that, as the fluid velocities increase, turbulence is needed in the fluid flow simulations to obtain agreement with experimental observations. The need for fine mesh and the incorporation of turbulence in[FS:PAGE] the fluid flow simulations for the phenomena taking place in the die casting shot sleeve have been noted in this work. Six simulations are provided in this section; 2 each, one for laminar and one with turbulence, for three different numbers of mesh. The total number of mesh used are 2,244, 24,000, and 60,000 cells in the same shot sleeve described in the introduction to this section.

Simulation Results

* Plunger velocity = 80cm/s, acceleration time = 0.1 sec, 50% fill, water density and viscosity, No surface tension

* Initial condition : flat free surface (There are no velocities in the fluid)

1. Mesh : 150*400, Turbulent

2. Mesh : 150*400, Laminar

3. Mesh : 80*300, Turbulent

4. Mesh : 80*300, Laminar

5. Mesh : 22*102, Turbulent

6. Mesh : 22*102, Laminar

Results and Conclusions:

As the plunger velocity increases, finer mesh size and/or a greater number of cells are required to obtain wave motions in keeping with those observed experimentally. Specifically, the larger number of cells and the incorporation of turbulence in the simulations are required to produce waves which both reach the top of the shot sleeve at the proper position or time during plunger movement and cascade in the fashion observed in the experimental water physical models. With insufficient number of cells and the lack of turbulence, the simulated waves formed during the plunger movement do not behave in keeping with the experimentally observed ones. A 150x400 mesh system and inclusion of the k-e turbulence model appear to adequately allow simulation of the wave dynamics associated with the shot sleeve portion of the die casting process.

B. 2-D Isothermal Model (Exponential Acceleration of the Plunger)

1.  Conditions for the 2-D Isothermal Simulations

The fluid used in these simulations : Pure Aluminum

Plunger velocities : 30, 60, and 80 cm/sec

Plunger accelerations : 1.5, 2.5, 4, 6, and 10 in/sec/in or cm/sec/cm

Surface tension values of Al : 670 dyne/cm (the surface tension of Al in a reducing gas environment)

3000 dyne/cm (the surface tension of Al with an oxide surface film)

Inlet velocity : 25 cm/sec

Shot sleeve filling time : 5 sec

Shot delay time : 0.4 sec

Shot Sleeve % fill : 50%

Height of the 2-D shot sleeve : 10 cm

Length of the 2-D shot sleeve : 50 cm

Pour hole diameter : 2 cm

k-epsilon turbulence model is used for all simulations.

2. The Plunger History for Several Different Acceleration Values

The fluid comes into the shot sleeve through the pour hole for the first 5 seconds and then dwells in the

shot sleeve for 0.4 second. The plunger does not move for the first 5.4 seconds, then the plunger is

accelerated until the plunger velocity reaches the slow shot velocity, after which the plunger velocity

remains constant at the selected shot slot velocity. Slow shot plunger velocities ranged from 30 to 80

cm/sec, and accelerations ranged from 1.5 to 10.0 in/sec/in. The acceleration unit sited here i[FS:PAGE]s not

cm/sec², but inch/sec/inch, because the latter unit is typically used in the die casting industry. When a

constant acceleration in units of in/sec/in is used, the plunger velocity increases exponentially with time.

The curves of plunger velocity versus time at several different acceleration values are shown in

Figure B.1.

Figure B.1. Plunger history at several different acceleration values

3. Results

1) The effect of plunger acceleration on the flow patterns:

              In these results, surface tension is not considered and plunger velocity is 60 cm/sec.

a. Plunger acceleration = 1.5 in/sec/in

b. Plunger acceleration = 2.5 in/sec/in

c. Plunger acceleration = 4 in/sec/in

d. Plunger acceleration = 6 in/sec/in

e. Plunger acceleration = 10 in/sec/in

For plunger accelerations of 1.5 and 2.5 in/sec/in, the waves curl  in front of the plunger but do not

form an entrapped gas pocket.  For the other accelerations (4, 6, and 10 in/sec/in), the wave in

front of the plunger curl and trap air in the shot sleeve. As the plunger acceleration increases, the

waves curl earlier, that is at a position nearer the pour hole. This indicates that the CSSV is

dependent on the plunger acceleration as well as plunger velocity.

2) The effect of plunger velocity and surface tension on the flow patterns:

In these results, the plunger acceleration is 2.5 in/sec/in.

a. Plunger velocity = 30 cm/sec, Surface tension value of Al = 670 dyne/cm

b. Plunger velocity = 30 cm/sec, Surface tension value of Al = 3000 dyne/cm

c. Plunger velocity = 60 cm/sec, Surface tension value of Al = 670 dyne/cm

d. Plunger velocity = 60 cm/sec, Surface tension value of Al = 3000 dyne/cm

e. Plunger velocity = 80 cm/sec, Surface tension value of Al = 670 dyne/cm

f. Plunger velocity = 80 cm/sec, Surface tension value of Al = 3000 dyne/cm

For the fixed plunger accleration (2.5 in/sec/in), when the plunger velocity is relatively low (30

cm/sec), a large amount of air is trapped in the liquid aluminum because the liquid is reflected from

the wall near the runner. When the plunger velocity is large, as in Figure B.2, the liquid aluminum

rolls over in front of the plunger, causing air entrapment. As the plunger velocity increases, air

entrapment decreases and then ncreases after a critical value (around 60 cm/sec). The plunger

velocity at the minimum air entrapment condition is the critical slow shot velocity (CSSV). The

existence of a critical slow shot velocity for minimizing air entrapment was previously predicted and

experimentally confirmed, as shown in simulations c and d, whose air entrapment is much less than

that associated with the other plunger velocities. When the plunger velocity is sufficient to cause

wave curling, the surface tension retards the curl. As the surface tension increases, the air

entrapment decreases [FS:PAGE]for the high plunger velocitie (compare simulations e and f). For plunger

velocities less than the CSSV (simulations a through d), the surface tension does not significantly

affect the wave patterns.

3) The relationship between plunger velocity and the amount of trapped air:

The relationship between plunger velocity and the amount of air entrapped obtained from these

simulations is quantitatively shown in Figure B.2. As the plunger velocity increases, the amount of

air entrapped decreases and then increases after a critical value plunger velocity is achieved. For

the 2.5 in/sec/in acceleration case,the Critical Slow Shot Velocity (CSSV) was between 60 and 65

cm/sec. For the 6.0 in/sec/in acceleration case, the amount of air entrapment is the least when the

plunger velocity is near 50 cm/sec. According to Thome's model[9], the CSSV is 57.1 cm/sec at

2.7 in/sec/in acceleration. The results of  Thome's model and the results of these simulations are in

qualitative agreement. The CSSV also depends on the plunger acceleration.The effect of plunger

acceleration on the amount of air entrapped is also shown in Figure B.2. According to Duran's

experiments[13], a plunger acceleration of 2 to 3 in/sec/in will minimize air entrapment for all initial

fill levels. The amount of air entrapped for 2.5 and 6.0 in/sec/in accelerations are compared in

Figure B.2. For plunger velocities greater than the CSSV, the amount of air entrapped is greater

with the larger plunger acceleration.The reason there is greater air entrapment for the larger plunger

acceleration (6 in/sec/in) is the wave begins curling earlier and curls with a smaller curvature. As the

plunger acceleration increases from a critical value (2 to 3 in/sec/in according to Duran's

experiments), the amount of air entrapment also increases.

Figure B.2. Percent Air Entrapment as a Function of Plunger Velocity and Acceleration

C. 2-D Athermal Model

1. Conditions for the 2-D Athermal Simulations

The fluid used in these simulation : Pure Aluminum

Plunger velocity : 80 cm/sec

Plunger acceleration : 2.5 in/sec/in or cm/sec/cm

Surface tension values of Al : 3000 dyne/cm (indicative of an oxide surface film)

Inlet velocity : 25 cm/sec

Shot sleeve filling time : 5 sec

Shot delay time : 0.1 - 16 sec

Shot Sleeve % fill : 50%

Height of the 2-D shot sleeve : 10 cm

Length of the 2-D shot sleeve : 50 cm

Pour hole diameter : 2 cm

k-epsilon turbulence model is used for all simulations

2. Thermal Properties of Aluminum , H-13 Shot Sleeve, and Copper Plunger Tip

3. Heat Transfer Coefficients (ergs/cm² sec K) [FS:PAGE]

1) Al and Shot sleeve / Air : 4.19E4

2) Shot sleeve / Liquid Al : 1.00E6

3) Shot sleeve / Plunger tip : 1.00E6 for no cooling of plunger tip

1.00E7 for cooling of plunger tip

4.Results

1) Comparison of isothermal  and athermal models

In these results, shot delay time is 0.4 sec. The color of the liquid aluminum indicates or scales with

the solid fraction. Red is 1 (100 % solid) and blue is 0 (100 % liquid).

a. Isothermal model

b. Athermal model

Based on the computer simulations, the wave patterns were not significantly affected by the

specified heat transfer conditions. .

2) The effect of residual waves on the athermal flow patterns

In these simulations, there is no cooling of plunger tip.

a. Shot delay time = 0.3 sec

b. Shot delay time = 0.4 sec

c. Shot delay time = 0.6 sec

d. Shot delay time = 0.8 sec

e. Shot delay time = 1.0 sec

f. Shot delay time = 1.3 sec

g. Shot delay time = 2.0 sec

For shot delay times of  0.3, 0.4, and 0.6 sec, the residual waves associated with the filling of the

shot sleeve move in the same direction as the plunger movement In those cases, (short shot delay

times), the residual waves do not interact with the wave generated by the plunger movement. For

shot delay times of  0.8, 1.0, and 1.3 sec, the residual waves associated with the shot sleeve filling

move in a direction opposite to the plunger movement. In those cases (longer shot delay times), the

residual waves interact with the wave generated by the plunger movement and increase the

amplitude of the resultant wave. The results of these simulations indicate that the residual waves

associated with filling interact with the waves generated by the plunger motion. The extend of

interaction depends on the timing of the initiation of plunger motion (the shot delay time) and the

specific plunger velocity and acceleration.

3) Solid fraction in filled shot sleeve for varying shot delay times (No cooling of plunger tip)

Figure C.1 shows the relationship between the solid fraction at the end of the slow shot (when the

shot sleeve is filled) or various shot delay times. The solid fraction at the end of slow shot

increases linearly with increasing shot delay time. Typically, the shot delay time is less than 1 sec

for diecasting processes. For the shot delay time of less than 1 sec, the solid fraction was predicted

to be around 3.0%.

Figure C.1. Solid fraction at the end of slow shot as a function of shot delay time

4) The effect of plunger tip cooling on the solid fraction

In these results, the shot delay time is 0.4 sec.

a. Cooling of copper plunger tip : i) shot sleeve filling and ii) slowshot

(Heat transfer coefficient between fluid and plunger tip :1.00E7 ergs/cm² sec K)

b. No cooling of H-13 plunger tip

(Heat transfer coefficient between fluid and plunger tip :1.00E6 ergs/cm² sec K)

For no cooling of plunger tip, solid fraction is about 2.7%, while solid fraction is abou[FS:PAGE]t 8.1% for

cooling of plunger tip. Thus, cooling of plunger tip increases solid fraction significantly according to

these simulation results.

Reference Related to Shot Sleeve Fluid Flow Phenomena:The following references relating to fluid flow studies and phenomena are provided:

1. Garber, L.W., "Some Preliminary Comments: Filling of the Cold Chamber during Slow Shot Travel," Die Casting Engineer, July-August, 36-38, 1981

2. Garber, L. W., "Theoretical Analysis and Experimental Observation of Air Entrapment during Cold Chamber Filling," Die Casting Engineer, May-June, 14-22, 1982

3. Karni, Y., "Selection of Process Variables for Die Casting," Report No.ERC/NSM-C-91-08, The Ohio State University, March, 1991

4. Tszeng, T. C. and Chu., Y. L., "A Study of Wave Formation in Shot Sleeve of a Die Casting Machine," Journal of Engineering for Industry, 116, 175-182, 1994

5. Dilks, S. D., "Wave Formation in Die Casting Machines," Master thesis, University of Rhode Island, 1983

6. Lopez, J. et al., "Shot Sleeve Wave Dynamics in the Slow Phase of Die Casting Injection," Journal of Fluids Engineering, 122, 349-356, 2000

7. Faura, F. et al., "On the Optimum Plunger Acceleration Law in the Slow Shot Phase of Pressure Die Casting Machines," International Journal of Machine Tools & Manufacture, 41, 173-191, 2001

8. Hernandez, J., Lopez, J., Gomez, P., Faura, F., "Influence of non-hydrostatic and viscous effect on shot sleeve wave dynamics in die casting injection", in: ASME/JSME Fluids engineering conference, Forum on Advances in Free Surface and Interface Fluid Dynamics, San francisco, USA, 248, 1999

9. Marilyn Thome. and Jerald R. Brevick, "Optimal Slow Shot Velocity Profiles For Cold Chamber Die Casting", North American Die Casting Association, October 2-5, 53-59, 1995

10. Backer, G. et al., "Using Finite Element Simulation for the Development of Shot Sleeve Velocity Profiles," NADCA Transactions, November, 17-20, 1997

11. Wang, L. et al., "Simulation of Flow Pattern and Temperature Profile in the Shot Sleeve of a High Pressure Die Casting Process," NADCA Transactions, Paper No. T01-014, 2001

12. Kim, H., "Investigation of the Influence of Shot Delay Time on Slow-Shot Profile via a Transparent Shot Sleeve and Water Model Analogy," Master Thesis, The Ohio State University, 1988

13. Duran, M. et al., "Minimization of Air Entrapment in the Shot Sleeve of a Die Casting Machine to Reduce Porosity," Report No. ERC/NSM-C-91-31, The Ohio State University, 1991

14. Armentrout, D. et al., "Investigation of the Slow Shot Phase to Minimize Entrapped Air in Cold Chamber Die Casting," Report No. ERC/NSM-C-93-19, The Ohio State University, June, 1993

15. Gordon, A.W. et al., "Comparison of Methods for Characterizing Porosity," Report No.RC/NSM-C-91-51, The Ohio State University, August 1991

16. Khayat, R.E., "A Three-dimensional Boundary Element Approach to Confined Free-surface Flow as Applied to Die Casting," Engineering Analysis with Boundary E[FS:PAGE]lements, 22, 83-102, 1998

17. Kuo, J.H. and Hwang, W.S., "Flow Pattern Simulation in Shot Sleeve During Injection of Diecasting," AFS Transactions, 106, 497-503, 1998

18. Sobol, D. et al., "Optimization of Shot Sleeve Performance," Die Casting Engineer, Vol 42, Iss 4, 61-65, 1998

19. Gershenzon, M. et al., "Formation of Cold Flakes in Aluminum High Pressure Die Casting," NADCA Transaction, Paper No. T99-085, 305-315, 1999

20. Prashant Shastri, B.E., "Experimental Determination of Thermal Conditions of Die Casting Shot Sleeves," Master thesis, The Ohio State University, 2001

21. Welch, J.E. et al., "The MAC Method: A Computing Technique for Solving Viscous, Incompressible, Transient Fluid-Flow Problems Involving Free Surfaces," Los Alamos Scientific Laboratory Report LA-3425, 1965

22. Amsden, A.A. and Harlow, F.H., "The SMAC Method: A Numerical Technique for Calculating Incompressible Fluid Flows," Los Alamos Scientific Laboratory Report LA-4370, 1970

23. Hirt, C.W. et al., "SOLA-A Numerical Solution Algorithm for transient Fluid

Flows," Los Alamos Scientific Laboratory Report LA-5852, 1975

24. Nichols, B.D. and Hirt, C.W., "SOLA-VOF: A Solution Algorithm for Transient Fluid Flow with multiple Free Boundaries," Los Alamos Scientific Laboratory Report LA-8355, 1980

25. Han, M., "Computer Aided Fluid Flow Studies Using Simplified Marker-and-cell Technique with Water Model Analogy Experiments within Die Casting Die Cavities," Master Thesis, The Ohio State University, 1989

26. Cleary, P. et al., "Flow modelling in Casting Processes", Applied Mathematical Modelling, Vol. 26, Iss. 2, 171-190, 2002

27. Ben-Ari, E. et al., "Simulating Filling and Solification of AZ91 Magnesium Alloy in Gravity Die Casting," Materials Technology, Vol. 16, Iss. 2, 133-141, 2001

28. Lee, S., and Sheu, S., "A New Numerical Formulation for Incompressible Viscous Free Surface Flow without Smearing the Free Surface," International Journal of Heat and Mass Transfer, Vol 44, Iss. 10, 1837-1848, 2001

29. Clark, L. D. et al., "Determination of Heat Transfer Coefficients Using a 1-D Flow Model Applied to Irregular Shaped Cooling Channels in Pressure Diecasting," Journal of Manufacturing Science and Engineering, Vol. 122, Iss. 4, 678-690, 2000

30. Xue, X. et al., "Numerical Simulation of Temperature Field of Die Casting Dies," Journal of Materials Science & Technology, Vol 17, Iss. 1, 95-96, 2001

31. Cleary, P. et al., "High Pressure Die Casting Simulation Using Smoothed Particle Hydrodynamics," International Journal of Cast Metals Research, Vol. 12, Iss. 6, 335-355, 2000

32. Cleary, P., and Ha, J., "Three Dimensional Modelling of High Pressure Die Casting," International Journal of Cast Metals Research, Vol. 12, Iss. 6, 357-365, 2000

33. Barone, M.R., and Caulk, D.A., "Analysis of Liquid Metal Flow in Die Casting," International Journal of Engineering Science, Vol. 38, Iss. 12, 1279-1302, 2000

34. Kim, N., and Kang, C., "An Investigation of Flow Characteristic[FS:PAGE]s Considering the Effect of Viscosity Variation in the Thixoforming Process," Journal of Materials Processing Technology, Vol. 103, Iss. 2, 237-246, 2000

35. Jia, L. R. et al., "Study on Numerical Simulation of Mold Filling and Heat Transfer in Die Casting Process," Journal of Materials Science & Technology, Vol. 16, Iss. 3, 269-272, 2000

36. Barkhudarov, M., "high Pressure Die Casting Simulation Using FLOW-3D," Die Casting Engineer, Vol. 41, Iss. 3, 36-36, 1997

37. Muttin, F. et al., "Numerical-Simulation of Inertial Effects in Newtonian Flows-Application to the Filling Stage of the Die-Casting Process," Journal of Materials Processing Technology, Vol. 31, Iss. 1-2, 65-74, 1992

38. Chan, K.S. et al., "Numerical-Simulation of Flows Encountered During Mold-Filling," Applied Mathematical Modelling, Vol. 15, Iss. 11-12, 624-631, 1991

39. Minaie, B. et al., "Analysis of Flow Patterns and Solidification Phenomena in the Die-Casting Process," Journal of Engineering Materials and Technology, Vol. 113, Iss. 3, 296-302, 1991

40. Barone, M.R., and Caulk, D.A., "A New Method for Thermal-Analysis of Die-Casting," Journal of Heat Transfer, Vol. 115, Iss. 2, 284-293, 1993

41. Schmidt, P., "Heat-Transfer During Filling in Die-Casting Processes," Materials Science and Engineering A - Structural Materials Properties Microstructure and Processing, Vol. 173, Iss. 1-2, 271-274, 1993

42. Lin, C.B. et al., "Analysis of Mold Flow and Microstructures of Die Casting in Al Alloy/SiC(p) composites," Journal of Materials Science, Vol. 34, Iss. 9, 2229-2240, 1999

43. Rosindale, I., and Davey, K., "Transient Thermal Model for the Hot Chamber Injection System in the Pressure Die Casting Process," Applied Mathematical Modelling, Vol. 23, Iss. 4, 255-277, 1999

44. Liu, G.W. et al., "Characterisation of the Spray Cooling Heat Transfer Involved in a High Pressure Die Casting Process," International Journal of Thermal Sciences, Vol. 39, Iss. 5, 582-591, 2000

1. the wave celerity and gas entrapment during the show shot stage of the process,

2. the fluidity of the alloy and its ability to completely fill the die cavity,

3. the microstructure of the resulting die casting, and

4. the mechanical properties of the resulting die casting.

This project is directed to extending the understanding of the effects of externally solidified product on the cold chamber die casting process and products to enable the production of defect-free diecastings and reduce the energy associated with these products. The projected energy savings from controlling the fraction of externally solidified product in die cast components is 0.04 quads (4*10¹³ BTU) through the year 2025.

The project involves three parallel activities:

1. Physical analog modeling with aqueous solutions under isothermal conditions with a second phase initially present on the shot sleeve wall, and a thermal conditions with solidification in transparent shot sleeves,

2. Computer modeling both the physical analog systems and aluminum die casting systems, and

3. Evaluating the quality of cold chamber die cast aluminum alloy components produced under controlled and monitored conditions with relatively small and large fractions of externally solidified products.

摘　要　回顾了世界煤矿的发展过程，全面介绍了采煤方法及其配套设备的研究内容和成果，通过对施工技术的完善、提高和推广，施工取得了快速、优质、经济的效果。

关键词　立井　凿井技术　快速施工　混合作业法　施工设备

1.　采场围岩控制技术

(1)进一步完善采场围岩控制理论。以科学合理、优化高效的岩层控制技术来保证开采活动的安全、高效、低成本为目标，深入总结我国几十年的矿山压力研究成果，以理论分析(解析法)、现代数学力学(统计分析预测、数值法)和实测法相结合运用先进的计算机技术，深入研究各种煤层地质及开采条件，如急倾斜、大采高、大采深采场矿山压力显现规律及围岩 破坏与平衡机理，不断完善采场围岩控制技术。

(2)研究坚硬顶板与破碎顶板条件下应用高技术低成本岩层控制技术。 目前，由于应用高压注水、深孔预裂爆破处理坚硬顶板和应用化学加固技术存在工艺复杂、成本高的问题， 因而需进一步研究开发新技术、新工艺、新材料来解决这些问题。

(3)放顶煤开采岩层和支架-围岩相互作用机理。研究放顶煤开采力学模型、围岩应力、顶煤破碎机理、支架-顶煤-直接顶-基本顶相互作用关系；运用离散元等方法研究顶煤放落 规律，提出放煤优化准则和提高顶煤回收率的途径。

(4)支护质量与顶板动态监测技术。在总结缓倾斜中厚长壁工作面开展支护质量与顶板动态监测方面，应进一步在坚硬顶板、破碎顶板、急倾斜、放顶煤工作面开展支护质量与顶板动态监测，同时应不断完善现有的监测技术，发展智能化监测系统，改进监测仪表，使监测仪表向直观、轻便、小型化方向发展。

(5)冲击地压的预测和防治。通过计算机模拟研究冲击性矿压显现发生的机理；进一步完善冲击性矿压显现监测系统，发展遥控测量和预报技术，完善冲击性矿压综合防治措施的优化 选择专家系统。

(6)研究开发新型的支护设备。研究硬煤层、硬顶板放顶煤液压支架，完善液压支架性能和 快速移架系统，开发耐炮崩、轻型化单体液压支柱和厚煤层巷道锚索和可伸缩锚杆。

①.缓倾斜薄煤层长壁开采。主要研究开发：体积小、功率大、高可靠性的薄煤层采煤机、刨煤机；研制适合刨煤机综采的液压支架；研究开发薄煤层工作面的总体配套技术和高效开采技术。

②缓倾斜厚煤层一次采全厚大采高长壁综采。应进一步加强完善支架结构及强度，加强支架防倒、防滑、防止顶梁焊缝开裂和四连杆变形、防止严重损坏千斤顶措施等的研究，提高支架的可靠性，缩小其与中厚煤层(采高3m左右)高产高效指标的差距。

③采煤方法和工艺的进步和完善始终是采矿学科发展的主题。采煤工艺的发展将带动煤炭开采各环节的变革，现代采煤工艺的发展方向是高产、高效、高安全性和高可靠性，基本途径是使采煤技术与现代高新技术相结合，研究开发强力、高效、安全、可靠、耐用、智能化的采煤设备和生产监控系统，改进和完善采煤工艺。在发展现代采煤工艺的同时，继续发展多层次、多样化的采煤工艺，建立具有中国特色的采煤工艺理论。我国长壁采煤方法已趋成熟， 放顶煤采煤的应用在不断扩展，应用水平和理论研究的深度和广度都在不断提高，急倾斜、 不稳定、地质构造复杂等难采煤层采煤方法和工艺的研究有很大空间，主要方向是改善作业 条件，提高单产和机械化水平。开发煤矿高效集约化生产技术、建设生产高度集中、高可靠性的高产高效矿井开采技术。以提高工作面单产和生产集中化为核心，以提高效率和经济效益为目标，研究开发各种条件下 的高效能、高可靠性的采煤装备和工艺，简单、高效、可靠的生产系统和开采布置，生产过程监控与科学管理等相互配套的成套开采技术，发展各种矿井煤层条件下的采煤机械化，进一步改进工艺和装备，提高应用水平和扩大应用范围，提高采煤机械化[FS:PAGE]的程度和水平。

④开发“浅埋深、硬顶板、硬煤层高产高效现代开采成套技术”，主要解决以下技术难题。硬顶板控制技术，研究埋深浅、地压小的硬厚顶板控制技术，主要通过岩层定向水力压裂、倾斜深孔爆破等顶板快速处理技术，使直接顶能随采随冒，提高顶煤回收率，且基本顶能按一定步距垮落，既有利于顶煤破碎，又保证工作面的安全生产。硬厚顶煤控制技术，研究开发埋深浅、支承压力小条件硬厚顶煤的快速处理技术，包括高压注水压裂技术和顶煤深孔预爆破处理技术，使顶煤体能随采随冒，提高其回收率。顶煤冒放性差、块度大的综放开采成套设备配套技术，研制既有利于顶煤破碎和顶板控制，又有利于放顶煤的新型液压支架，合理确定后部输送机能力。两硬条件下放顶煤开采快速推进技术，研究合适的综放开采回采工艺，优化工序，缩短放煤时间，提高工作面的推进度，实现高产高效。5～5.5m宽煤巷锚杆支护技术，通过宽煤巷锚杆支护技术的研究开发和应用，有利于综采配套设备的大功率和重型化，有助于连续采煤机 的应用，促进工作面的高产高效。

⑤各种综采高产高效综采设备保障系统。要实现高产高效，就要提高开机率，对“支架 -围岩”系统、采运设备进行监控。今后研究的重点是：通过电液控制阀组操纵支架和改善“支架-围岩”系统控制，进一步完善液压信息、支架位态、顶板状态、支护质量信息的自动采集系统；乳化液泵站及液压系统运行状态的检测诊断；采煤机在线与离线相结合的“油 -磨屑”监测和温度、电信号的监测；带式输送机、刮板输送机全面状态监控。

2　深矿井开采技术

深矿井开采的关键技术是：煤层开采的矿压控制、冲击地压防治、瓦斯和热害治理及深井通 风、井巷布置等；需要攻关研究的是：深井围岩状态和应力场及分布状态的特征；深井作业场所工作环境的变化；深井巷道(特别是软岩巷道)快速掘进与支护技术与装备；深井冲击地压防治技术与监测监控技术；深矿井高产高效开采有关配套技术；深矿井开采热害治理技术 与装备。

3“三下”采煤技术

提高数值模拟计算和相似材料模拟等，深入研究开采上覆岩层运动和地表沉陷规律，研究满足地表、建筑物、地下水资源保护需要的合理的开采系统和优化参数，发展沉降控制理论和关键技术，包括用地表废料向垮落法工作面采空区充填的系统；研究与应用各种充填技术和组合充填技术，村庄房屋加固改造重建技术，适于村庄保护的开采技术；研究近水体开采的开采设计、工艺参数优化和装备，提出煤炭开采与煤矿城市和谐统一的开采沉陷控制、开采 村庄下压煤、土地复垦和矿井水资源化等关键技术。

4　优化巷道布置，减少矸石排放的开采技术

改进、完善现有采煤方法和开采布置， 以实现开采效益最大化为目标，研究开发煤矿地质条件开采巷道布置及工艺技术评价体系专家系统，实现开采方法、开采布置与煤层地质条件 的最优匹配。总结推广神华集团大柳塔矿、潞安漳村矿实行全煤巷布置单一煤层开采，矸石基本不运出地面，生产系统大大简化，分别实现无轨胶轮、单轨吊辅助运输一条龙，从井口直达工作面， 同时实现了综采与综掘同步发展，生产效率大幅提高的经验的同时，重点研究高产高效矿井开拓部署与巷道布置系统的优化，简化巷道布置，优化采区及工作面参数，研究单一煤层集中开拓，集中准备、集中回采的关键技术，大幅度降低岩巷掘进率，多开煤巷，减少出矸率；研究矸石在井下直接处理、作为充填材料的技术，既是减少污染的一项有力措施，又简化 了生产系统，有利于高产高效集中化开采，应加紧研究。

5　小煤矿技术改造和机械化开采技术

实施国家关闭小煤矿，淘汰落后生产技术和生产设备，提高平均单井规模的技术政策，开发小型煤矿机械化、半机械化开采技术和装备，改进小煤矿的采煤方法和[FS:PAGE]开采工艺，提高采煤工作面的单产和工效；提高小煤矿的顶底板控制技术水平，最大限度地减少顶底板事故率。

6　煤炭地下气化技术

煤炭地下气化技术是将处于地下的煤炭进行有控制的燃烧，通过对煤的热化学作用而产生可燃气体的过程。煤炭地下气化技术属于一种特殊的采煤方法，它属国际首创。煤炭地下气化技术具有投资少、工期短、见效快、用人少、效率高、成本低、效益好等优点，尤其适合我国煤矿地质条件复杂、劣质煤比例高、“三下”压煤严重的具体国情，具有广阔的推广应用前景。应继续研究完善“长通道、大断面、两阶段”和“矿井式气化”两种典型煤炭地下气化工艺，进行较大规模的地下气化试验研究，摸索实现“两个控制、三个稳定”的技术途径，并实现连续、稳定生产探索应用的途径。

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[4]尼尔 米奇森 ,乔治 A. 帕帕扎基斯 ,SevesoII下的安全管理系统 ：实施和评价.制造业防损期刊 44/3, 1998, 172–80

[5]比吉特 瑞斯姆森纳,库尔特 E. 彼得森.设置函数模型作为评定安全管理设备的基础 .可靠性技术与系统安全性. 14, 1999, 2883–8

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[8]格奇 D L. 技术员,工程师和管理员的职业安全和健康 , 新泽西州 :普伦蒂塞学院 ,1999

the development of the coal mine

Abstract Recalling our operations in coal mine of the development process, comprehensive presentation of a short driving and masonry mixed law and its supporting equipment research and findings，Well antagonism through rapid construction techniques improve, enhance and promote the construction of shaft over the rapid, high-quality, and the economy.

Keywords Shaft Sinking Fast mixed construction method for construction equipment

1.Adopt the field round the rock control technique

(1)It is further perfect to adopt the field rounds the rock the control the theories.With the reasonable and excellent rock strata turning efficiently in science controls the technique to the safety that assurance mine the activity, efficiently, low cost for target, go deep into the mineral mountain pressure research result that tally up several decades of our countries, analyze( analyze method) with the theories, modern mathematics mechanics( statistics analysis estimate, number method) with solid measure the calculator technique that method combine together application forerunner, thorough research every kind of coal seam geology and mine the term, such as the nasty inclination, big adopt the high and big adopting deep adopt a mineral mountain pressure present the regulation and round the rock breaks and equilibrium mechanism, continuously perfect adopt the field round the rock control technique.

（2)Research the strong and tough a plank is next with broken up a lath piece to apply the low cost rock strata in high technique the control the tec[FS:PAGE]hnique. Current, because of applying the high pressure notes the water, deep bore prepares the blows up to handle strong and tough a plank with apply the chemistry reinforces the technique exsits craft complicacy, high problem in cost, as a result need the further research develop the new technique, new craft, new material to resolve these problemses.

(3)Putting a coal mines the rock strata with the a- round the rock interaction mechanism.The research puts a coal mine the mechanics model and round the rock in response to the dint, crest coal broken up mechanism,- a coal- direct crest- basic an interaction relation;Making use of long-lost an etc. method research a coal puts to fall the regulation, putting forward to put the coal the excellent turning the standard with a coal that increases the path recovers the rate.

(4)A quantity monitors with crest plank development technique.In tally up tilt to one side the thick long wall works opens the exhibition a quantity monitors with crest plank development aspect, should be further at the strong and tough a plank, fall in pieces a plank, nasty inclination and put a coal the work open the exhibition a quantity monitors with crest plank development, at the same time should continuously perfect monitors currently technique, develop the in telligence turns to monitor system, improvement monitor appearance, make monitors gauge face keep the view, easy and convenient, small scaled turn the direction development.

(5)Pound at an estimate for pressing with the prevention and cure.Passing the calculator emulation research impact mineral presses the mechanism that present the occurrence;Further over pound at well the sex mineral presses to present to monitor system, the development controls from a distance the diagraph with forecast the technique, the perfect impact mineral presses to synthesize the prevention and cure measure excellent to turn to choose the expert system.

(6)The research develops the new a equipments.Hard coal seam in research, the hard a plank puts a coal liquid presses a, the perfect liquid presses a function with move a system quickly, the development bears the firecrackers collapses, light turn the single body fluid press a pillar with the thick coal seam tunnel anchor man  with flexible anchor man pole.

2.  Adopt the coal method with the craft

①The long wall in thin coal seam in inclination in mines.Main research development:The eclipse stirs up to chew th Research to manufacture coal machine that suiting and planing the liquid adopts to press a; The research develops the total kit technique that thin coal seam work with mine the technique efficiently

(2)he tilts to one side the thick coal seam an adopting all and thick and big adopt the high and long wall adopt.Should further enhance perfect a construction and strengths, enhance a research for defends to pour, antiskidly, keeping a beam from sewing to open the with fourth connecting the pole transform, prevent serious[FS:PAGE]ly damaging the jack measure wait, exaltation a margin for of dependable, contracting its with thick coal seam( adopt the high 3 ms is or so) in inside highly producing efficiently index sign.

（3）Adopt the coal method with the advance of the craft and perfect the alpha and omega is a topic that mine for minerals course's development.Development that adopt the coal craft will arouse the coal mines each link replaces, modern adopt the development direction of the coal craft is a high producing, efficiently, high safety with high and dependable, the basic path is to makes adopt the coal technique combine together with high and new technique in modern, studying to develop the strong dint, efficiently, safety, dependable, enduring, the intelligence turn of adopt the coal equipments with produce to supervise and control the system, improve with perfect adopt the coal craft.At develop modern adopt the coal craft at the same time, continue development many level of structure, adopt the coal craft diversification, establish to have China to adopt the coal craft theories characteristicly.The development coal mine is efficiently intensive to turn the production technique, developments the production the high degree concentrates, high and dependable and sexual and high produce efficiently the mineral well mines the technique.To increase the work is single to produce with produce concentration change into the core, then lift high-efficiency with economic performance for target, study high performance that develop every kind of term's bottom, high and dependable adopt the coal the material sexually with craft, simple, efficiently, dependable production system with mine to arrange, the production line supervise and control to manage with science etc. mutually kit of the set mines the technique, developping every kind of mineral well coal seam term descend of adopt the coal mechanizes, further improving the craft with equip, increases to apply the level with extend the application, increase degree that adopt coal's mechanization with level.

(4) The " shallow is be the deep and hard a plank, hard coal seam is high to produce efficiently modern mine a technique" of development, main solution below technique hard nut to crack.Hard a plank control technique, study the  deep shallow, a safe production for pressing small hard and thick a plank control technique, primarily passing rock strata definite direction water power pressing , tilting to one side deep bore blowing up waiting first crest the plank dispatches the technique, making directly crest can with adopting with the tip , exaltation a coal recovery rate, and the basic crest can press the certain step is apart from the falls, since benefit to a coal broken uply, guaranteeing the work again.Hard and thick a coal control technique, the research development is deep shallow, accepts the hard and thick crest in small term in pressure dispatches the technique coalyly, including the high pres[FS:PAGE]sure notes the water pressure technique to prepares to blow up to handle with the deep bore in a coal technique, make a coal physique with adopt with the increase its recovery rate。Two hard terms descend to put a propulsion for the coal mines the fleetness propulsion technique, studying fit releasing adopting returning adopting craft, excellent chemical engineering preface, shortenning putting coal time, increasing work degree, realize the high producing is efficiently.5 ～ a breadth coal lane anchor man pole a technique, pass the technical research in pole in anchor man in lane in coal in breadth the development and application, benefit to the big power that adopt the kit equipments to turn with heavy type, is beneficial to the application that consecution adopt the coal the machine, promote the work high to produce efficiently.

(5) every kind of adopts the high producing efficiently the adopts the equipments guarantees system.Toing realizes high producing is efficiently, will increase to open the probability, to" a- round the rock" system, adopt to carry the equipments proceed to supervise and control.From now on the point that study is:Pass to give or get an electric shock the liquid control valve set manipulate a with improve" a- round the rock" the system controls, the further perfect liquid presses the information,the crest plank appearance, quantity information of collect the system automatically;Emulsifying the liquid pump stands and the liquid presses the examination diagnosis that system circulate appearance;Adopt the coal machine on-line and off-line combine together of" oil- whet the scraps" monitors to monitors with the temperature, telecommunication number;The take type transports the machine and pare off the plank transport the machine the appearance to supervise and control completely.

he deep mineral well mines the technique

Key technique that deep mineral well mine is:The mineral that coal seam mine presses the control and pound at the ground presses the prevention and cure, gas to harm to manage with the heat and the deep well is well ventilated, the well lane arranges etc.;Needing to offend pass investigative is: The deep well rounds the rock appearance with should dint a characteristic for and distributing appearance; The variety of the deep well homework place work environment; The deep well tunnel( especially soft rock tunnel) digs into quickly with a technique and material; The deep well impact ground presses the prevention and cure technique with monitors to supervise and control the technique; The deep mineral well is high to produce to mine the relevant kit technique efficiently; The deep mineral well mines the heat harms to manage the technique and material.

3 " three times" adopt the coal technique

The exaltation number imitates the calculation with resembles material imitate etc., Thorough the research mine the rock strata of exercise to sink to sink the regulation with earth's surface, studying satisfy [FS:PAGE]the earth's surface, building, groundwater resources protects the reasonable of the demand mines the system with excellent turn the parameter, develop to sink to decline to control the theories with key technique, include to use the earth's surface waste fall to method work adopts the system that get empty area fill; Research and applied every kind of fills the technique with combine the fills the technique, the village house reinforces to reform reconstruction technique, be suitable for the village to mine the technique protectively; Studying the near of water mines of mine the design, craft parameter the excellent turning with equip, put forward the coal mine to harmonize to unify with the coal mine city of mine to sink to sink the control and mine the village descend press the coal, land replies the with mineral well water recycling etc. Key technique.4 Excellent turn the tunnel arrange, reducing the exhaust of mine the technique.

Improvement, perfect and current adopt the coal method with mine to arrange, to realize to mine the performance the biggest changing into the target, the research develops the coal mine geology term mines the tunnel arranges and the craft technique evaluates the system expert system, realizing to mine the method and mine to arrange with coal seam geology term of superior match.The summary expands the peaceful in mineral in tower in big in group in absolute being village mineral practices the whole coal lane arranges the one coal seam mines, basic do not deliver the ground, produce the system to simplify consu medly, realizes to have no the gum respectively round, single track mourn the assistance transports a dragon, from the mouth of a well go directly to the work, realizes at the same time the  adopts to dig with the synchronous development, producing the efficiency increases significantly of empirical at the same time, point research high produce efficiently the mineral well expands to deploy to arrange with tunnel the system of excellent turn, simplify the tunnel arranges, excellent turn to adopt the area and work the parameter, study the one coal seam concentrates to expand, concentrating preparation, concentrates to return to the key technique that adopt, significant lower the rock lane digs into the rate, openning coal lane more, reducing the rate of the stones to under the well handles directly, the conduct and actions fills the technique of the material, since is to reduce contaminative an emollient measure, simplifying the production system again, benefitting to the high producing to concentrates to turn to mine efficiently, shoulding step up the research.

4. The small coal mine technique reforms with mechanize to mine the technique

Put the nation closes the small coal mine, eliminating to fall behind the production technique with produce the equipments, increasing into practice the technique policy of the average and single well scale, develop the small scaled coal mine the mechanization, [FS:PAGE]half the mechanization mine the technique with equip, improving the small coal mine adopts the coal method with mine the craft, increase to adopt coal work of single produce with work effect;A scaleboard of the small coal mine in exaltation controls the technique level, the biggest limit ground reduces a scaleboard trouble rate.

5.The coal underground gasifies the technique

The coal underground gasification technique is to will be placed in the underground coal proceed to have the combustion of the control, passing to the coaly and hot chemical effect but produce the combustible and gaseous process.The coal underground gasification technique belongs to a kind of adopting the coal method specially, it belong to nations found.The coal underground gasification technique has the investment little, the work period is short and take effect quick, use the person little, the efficiency is high, the cost is low, good etc. in performance advantage, particularly in keeping with our country coal mine geology term complicacy, the inferior coal comparison is high," three times" press the coal the concrete state of the nation seriously, have vast expansion application foreground.Should continue to study perfect" grow the passage, big cross section, two stages" with" mineral well type the gasification" two kinds of typical models coal underground gasify craft, proceed the large-scale underground gasify the on trial research, grope for the technique path that realizes the " two controls, three stability", and realizes consecution, stabilize to produce the applied path in quest.

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The braking system is the most important system in cars. If the brakes fail, the result can be disastrous. Brakes are actually energy conversion devices, which convert the kinetic energy (momentum) of the vehicle into thermal energy (heat).When stepping on the brakes, the driver commands a stopping force ten times as powerful as the force that puts the car in motion. The braking system can exert thousands of pounds of pressure on each of the four brakes.

Two complete independent braking systems are used on the car. They are the service brake and the parking brake.

The service brake acts to slow, stop, or hold the vehicle during normal driving. They are foot-operated by the driver depressing and releasing the brake pedal. The primary purpose of the brake is to hold the vehicle stationary while it is unattended. The parking brake is mechanically operated by when a separate parking brake foot pedal or hand lever is set.

The brake system is composed of the following basic components: the “master cylinder” which is located under the hood, and is directly connected to the brake pedal, converts driver foot’s mechanical pressure into hydraulic pressure. Steel “brake lines” and flexible “brake hoses” connect the master cylinder to the “slave cylinders” located at each wheel. Brake fluid, specially designed to work in extreme conditions, fills the system. “Shoes” and “pads” are pushed by the slave cylinders to contact the “drums” and “rotors” thus causing drag, which (hopefully) slows the car.

The typical brake system consists of disk brakes in front and either disk or drum brakes in the rear connected by a system of tubes and hoses that link the brake at each wheel to the master cylinder (Figure).

Basically, all car brakes are friction brakes. When the driver applies the brake, the control device forces brake shoes, or pads, against the rotating brake drum or disks at wheel. Friction between the shoes or pads and the drums or disks then slows or stops the wheel so that the car is braked.

In most modern brake systems (see Figure 15.1), there is a fluid-filled cylinder, called master cylinder, which contains two separate sections, there is a piston in each section and both pistons are connected to a brake pedal in the driver’s compartment. When the brake is pushed down, brake fluid is sent from the master cylinder to the wheels. At the wheels, the fluid pushes shoes, or pads, against revolving drums or disks. The friction between the stationary shoes, or pads, and the revolving drums or disks slows and stops them. This slows or stops the revolving wheels, which, in turn, slow or stop the car.

The brake fluid reservoir is on top of the master cylinder. Most cars today have a transparent r reservoir so that you can see the level without opening the cover. The brake fluid level will drop slightly as the brake pads wear. This is a normal condition and no cause for concern. If the level drops noticeably over a[FS:PAGE] short period of time or goes down to about two thirds full, have your brakes checked as soon as possible. Keep the reservoir covered except for the amount of time you need to fill it and never leave a cam of brake fluid uncovered. Brake fluid must maintain a very high boiling point. Exposure to air will cause the fluid to absorb moisture which will lower that boiling point.

The brake fluid travels from the master cylinder to the wheels through a series of steel tubes and reinforced rubber hoses. Rubber hoses are only used in places that require flexibility, such as at the front wheels, which move up and down as well as steer. The rest of the system uses non-corrosive seamless steel tubing with special fittings at all attachment points. If a steel line requires a repair, the best procedure is to replace the compete line. If this is not practical, a line can be repaired using special splice fittings that are made for brake system repair. You must never use copper tubing to repair a brake system. They are dangerous and illegal.

Drum brakes, it consists of the brake drum, an expander, pull back springs, a stationary back plate, two shoes with friction linings, and anchor pins. The stationary back plate is secured to the flange of the axle housing or to the steering knuckle. The brake drum is mounted on the wheel hub. There is a clearance between the inner surface of the drum and the shoe lining. To apply brakes, the driver pushes pedal, the expander expands the shoes and presses them to the drum. Friction between the brake drum and the friction linings brakes the wheels and the vehicle stops. To release brakes, the driver release the pedal, the pull back spring retracts the shoes thus permitting free rotation of the wheels.

Disk brakes, it has a metal disk instead of a drum. A flat shoe, or disk-brake pad, is located on each side of the disk. The shoes squeeze the rotating disk to stop the car. Fluid from the master cylinder forces the pistons to move in, toward the disk. This action pushes the friction pads tightly against the disk. The friction between the shoes and disk slows and stops it. This provides the braking action. Pistons are made of either plastic or metal. There are three general types of disk brakes. They are the floating-caliper type, the fixed-caliper type, and the sliding-caliper type. Floating-caliper and sliding-caliper disk brakes use a single piston. Fixed-caliper disk brakes have either two or four pistons.

The brake system assemblies are actuated by mechanical, hydraulic or pneumatic devices. The mechanical leverage is used in the parking brakes fitted in all automobile. When the brake pedal is depressed, the rod pushes the piston of brake master cylinder which presses the fluid. The fluid flows through the pipelines to the power brake unit and then to the wheel cylinder. The fluid pressure expands the cylinder pistons thus pressing the shoes to the drum or disk. If the pedal is released, the piston returns to the initial[FS:PAGE] position, the pull back springs retract the shoes, the fluid is forced back to the master cylinder and braking ceases.

The primary purpose of the parking brake is to hold the vehicle stationary while it is unattended. The parking brake is mechanically operated by the driver when a separate parking braking hand lever is set. The hand brake is normally used when the car has already stopped. A lever is pulled and the rear brakes are approached and locked in the “on” position. The car may now be left without fear of its rolling away. When the driver wants to move the car again, he must press a button before the lever can be released. The hand brake must also be able to stop the car in the event of the foot brake failing. For this reason, it is separate from the foot brake uses cable or rods instead of the hydraulic system.

Anti-lock Brake System

Anti-lock brake systems make braking safer and more convenient, Anti-lock brake systems modulate brake system hydraulic pressure to prevent the brakes from locking and the tires from skidding on slippery pavement or during a panic stop.

Anti-lock brake systems have been used on aircraft for years, and some domestic car were offered with an early form of anti-lock braking in late 1990’s. Recently, several automakers have introduced more sophisticated anti-lock system. Investigations in Europe, where anti-lock braking systems have been available for a decade, have led one manufacture to state that the number of traffic accidents could be reduced by seven and a half percent if all cars had anti-lock brakes. So some sources predict that all cars will offer anti-lock brakes to improve the safety of the car.

Anti-lock systems modulate brake application force several times per second to hold the tires at a controlled amount of slip; all systems accomplish this in basically the same way. One or more speed sensors generate alternating current signal whose frequency increases with the wheel rotational speed. An electronic control unit continuously monitors these signals and if the frequency of a signal drops too rapidly indicating that a wheel is about to lock, the control unit instructs a modulating device to reduce hydraulic pressure to the brake at the affected wheel. When sensor signals indicate the wheel is again rotating normally, the control unit allows increased hydraulic pressure to the brake. This release-apply cycle occurs several time per second to “pump” the brakes like a driver might but at a much faster rate.

In addition to their basic operation, anti-lock systems have two other things in common. First, they do not operate until the brakes are applied with enough force to lock or nearly lock a wheel. At all other times, the system stands ready to function but does not interfere with normal braking. Second, if the anti-lock system fail in any way, the brakes continue to operate without anti-lock capability. A warning light on the instrument panel alerts the driver when a problem exists in th[FS:PAGE]e anti-lock system.

The current Bosch component Anti-lock Braking System (ABSⅡ), is a second generation design wildly used by European automakers such as BWM, Mercedes-Benz and Porsche. ABSⅡ system consists of : four wheel speed sensor, electronic control unit and modulator assembly.

A speed sensor is fitted at each wheel sends signals about wheel rotation to control unit. Each speed sensor consists of a sensor unit and a gear wheel. The front sensor mounts to the steering knuckle and its gear wheel is pressed onto the stub axle that rotates with the wheel. The rear sensor mounts the rear suspension member and its gear wheel is pressed onto the axle. The sensor itself is a winding with a magnetic core. The core creates a magnetic field around the winding, and as the teeth of the gear wheel move through this field, an alternating current is induced in the winding. The control unit monitors the rate o change in this frequency to determine impending brake lockup.

The control unit’s function can be divided into three parts: signal processing, logic and safety circuitry. The signal processing section is the converter that receives the alternating current signals form the speed sensors and converts them into digital form for the logic section. The logic section then analyzes the digitized signals to calculate any brake pressure changes needed. If impending lockup is sensed, the logic section sends commands to the modulator assembly.

Modulator assembly

The hydraulic modulator assembly regulates pressure to the wheel brakes when it receives commands from the control utuit. The modulator assembly can maintain or reduce pressure over the level it receives from the master cylinder, it also can never apply the brakes by itself. The modulator assembly consists of three high-speed electric solenoid valves, two fluid reservoirs and a turn delivery pump equipped with inlet and outlet check valves. The modulator electrical connector and controlling relays are concealed under a plastic cover of the assembly.

Each front wheel is served by electric solenoid valve modulated independently by the control unit. The rear brakes are served by a single solenoid valve and modulated together using the select-low principle. During anti-braking system operation, the control unit cycles the solenoid valves to either hold or release pressure the brake lines. When pressure is released from the brake lines during anti-braking operation, it is routed to a fluid reservoir. There is one reservoir for the front brake circuit. The reservoirs are low-pressure accumulators that store fluid under slight spring pressure until the return delivery pump can return the fluid through the brake lines to the master cylinder.

汽车制动系统

制动系统是汽车中最重要的系统。 如果制动失灵，结果可能是损失惨重的。制动器实际就是能量转换装置，它将汽车的动能（动量）转化成热能（热量）。当驾驶员踩下制动踏板，所产生的制动力是汽车运动时动力的10倍。制动系统能对四个刹车系统中的每个施加数千磅的力[FS:PAGE]。

每辆汽车上使用两个完全独立的制动系统，即行车制动器和驻车制动器。

行车制动器起到减速、停车、或保持车辆正常行驶。制动器是由司机用脚踩、松制动器踏板来控制的。驻车制动器的主要作用就是当车内无人的时候，汽车能够保持静止。当独立的驻车制动器—踏板或手杆，被安装时，驻车制动器就会被机械地操作。

制动系统是由下列基本的成分组成:位于发动机罩下方，而且直接地被连接到制动踏板的“制动主缸”把驾驶员脚的机械力转变为液压力。钢制的“制动管路”和有柔性的“制动软管”把制动主缸连接到每个轮子的“制动轮缸”上。 制动液, 特别地设计为的是工作在极端的情况，填充在系统中。“制动盘”和“衬块”是被制动轮缸推动接触“圆盘”和“回转体”如此引起缓慢的拖拉运动, (希望)使汽车减慢速度。

典型的制动系统布置有前后盘式，前盘后鼓式，各个车轮上的制动器通过一套管路系统连接到制动主缸上。

基本上讲，所有的汽车制动器都是摩擦制动器。当司机刹车时，控制装置会迫使制动蹄，或制动衬片与车轮处的旋转的制动鼓或制动盘接触。接触后产生的摩擦使车轮转动减慢或停止，这就是汽车的制动。

在最基本的制动系统中，有一个制动主缸，这个主缸内部填充制动液，并包含两个部分，每个部分里都有一个活塞，两个活塞都连接驾驶室里的制动踏板。当制动踏板被踩下时，制动液会从制动主缸流入轮缸。在轮缸中，制动液推动制动蹄或制动衬片与旋转的制动鼓或制动盘接触。静止的制动蹄或制动衬片与旋转的制动鼓或制动盘之间产生摩擦力使汽车的运动逐渐减缓或停止。

制动液的装置位于主缸的顶部。目前大多数的车都有一个容易看见的装制动液的装置，为的是不用打开盖子就可以看得见制动液的油面。随着制动踏板的运动制动液就会缓慢的下降，正常情况下是这样的。如果制动液在很短的时间内下降得明显或者下降了三分之二，那么就要尽快的检查你的制动系统了。保持制动液装置充满制动液除非你需要维修它，制动液必须保持很高的沸点。位于在空气中的制动液就会吸收空气中的潮气引起制动液低于沸点。

制动液通过一系列的管路从主缸到达各车轮。橡胶软管只用在需要弹力的地方，比如应用在前轮。在车的行进中上下来回运动。系统的其它部分在所有的连接点上都应用了无腐蚀性的无缝钢管。如果钢线需要修理的话，最好的方法就是代替这条线。如果这不符合实际，那么为了制动系统可以用特殊的装置修理它。你不可以用铜管来修理制动系。它们是危险也是不正确的。

鼓式制动器包括制动鼓，一个轮缸，回拉弹簧，一个制动底版，两个带摩擦层的制动蹄。制动底版固定在轮轴外部的法兰或转向节。制动鼓固定在轮毂上。制动鼓的内部表面与制动蹄的内层之间有空隙。要使用制动器时，司机就要踩下踏板，这时轮缸扩大制动片，对其施加压力，是制动蹄触碰制动鼓。制动鼓与摩擦片之间产生的摩擦制动了车轮，从而使汽车停止。要释放制动器时，司机松开踏板，回拉弹簧拉回制动片，这样车轮会自由转动。

盘式制动器包括制动盘而不是鼓，在它的两面上各有一个薄的制动片或叫盘式制动器的制动片。制动片是靠挤住旋转的制动盘来停住汽车。制动主缸里流出的制动液迫使活塞向里部的金属盘移动，这便使摩擦片紧紧地贴住制动盘。这时制动片与制动盘产生的摩擦使汽车减速、停止，出现了制动行为。活塞分金属或塑料。盘式制动器主要有三种，即：浮动卡钳型、固定卡钳型和滑动卡钳型。浮动卡钳型和滑动卡钳型盘式制动器使用单活塞。固定卡钳型盘式制动器既可以使用两个活塞有可以使用四个活塞。

制动系统是由机械能，液压能或气压能装置驱动的。在机械杠杆适合所有的汽车的驻车制动器中使用。当踩下制动踏板时，杠杆就会推动制动器主缸的活塞给制动液施加压力，制[FS:PAGE]动液通过油管流入轮缸。制动液的压力施加到轮缸活塞以使制动片被压到制动鼓或制动盘上。如果松开踏板，活塞回到原来的位置上，回拉弹簧拉回制动片，制动液返回制动主缸，这样制动停止。

驻动制动器的主要作用是车内无人时，使汽车静止不动。如果车内安装的是独立的驻车制动器，那么驻车制动器是由司机手动的控制。驻车制动器正常是当车已经停止时使用的。向后拉手闸，并把手柄卡在正确的位置上。现在，即使离开汽车也不用害怕它会自己滑走。如果司机要再次启车时，他必须在松开手杆之前按下按钮。在行车制动器失灵的情况下，手闸必须能停住车。正因为这样，手闸与脚闸分开，手闸使用的是绳索或杠杆而不是液力系统。

防抱死制动系统是使汽车制动更安全、更方便的制动装置，它既有调节制动系统的压力来防止车轮被完全抱死的功能，又有防止轮胎在滑的路面上行驶或紧急停车时的滑动。

防抱死制动系统最早应用在航空飞行器上，而且在二十世纪 90年代一些国内的汽车内也安装了这种系统。近来，几个汽车制造商引进了更为复杂的防抱死系统。欧洲使用这种系统已有几十年的时间，通过对其的调查，一位汽车制造商坦言，如果所有的汽车都安装上防抱死制动系统，那么交通事故的发生率会降低7.5%。同时，一些权威人士预测这种系统会提高汽车的安全性。

防抱死制动系统可以在一秒钟内调节几次制动时车轮上的受力，使车轮的滑移受到控制，而且所有的系统基本上都以相同的方式完成。每个车轮都会有一个传感器，电子控制装置能连续检测来自车轮传感器传来的脉冲电信号，并将它们处理转换成和轮速成正比的数值；如果其中一个传感器的信号不断下降，那么这就表明了相应的轮胎趋于抱死，这时电子控制装置向该车轮的制动器发出降低压力的指令。当信号显示车轮转速恢复正常时，电子控制装置会增加制动器的液压。这种循环像司机一样调节制动器，但它的速度更快，达到了每秒循环数次。

防抱死制动系统除了上面基本操作，还有两个特点。首先，当制动系统的压力上升到使轮胎抱死或即将抱死的时候，防抱死制动系统才会启动；当制动系统在正常情况下，防抱死制动系统停止运作。其次，如果防抱死制动系统有问题时，制动器会独立地继续运行。但控制板上的指示灯亮起提醒司机系统出现问题。

目前欧洲汽车生产商，如：宝马、奔驰、宝时捷等广泛使用的是波许（Bosch）防抱死制动系统。这种系统基本组成包括车轮转速传感器，电子控制装置和调节装置。

每个有一个向电子控制装置发出车轮转动情况的信号的传感器，它一般由磁感应传感头和齿圈组成。前面的传感器安在轮毂上，齿圈安在轮网上。后面的传感器安在后部的监测系统上，齿圈安在轮轴上。传感器本身是缠绕电磁核的电线圈，电磁核才线圈的周围产生磁场。当齿圈的齿移动到磁场时，就会改变线圈的电流。电子控制装置会监测这种变化，然后判断车轮是否即将抱死。

电子控制装置有三个作用，即：信号的处理，编辑和安全防护。信号的处理起到转换器的作用，它是将接受的脉冲电信号处理转换成数值，为编辑做准备。编辑就是分析这些数值，计算出需要制动压力。如果检测出车轮即将抱死，电控装置就会计算出数值向调节装置发出指令。

调节装置

当接受到电子控制装置的指令后，液压执行装置会调节制动轮缸的液压的大小。调节装置能保持或减小来自制动主缸的液压，而装置本身是不能启用制动器的。这种装置有三个高速率的电磁阀，两个油液存储器和一个带有内外检测阀的传动泵。调节装置中的电子连接器隐藏在塑料盖下。

每个电磁阀都是其独立控制的，并作用于前轮。后部的制动轮缸受到一个电磁阀控制，并依照------的原理进行调节。当防抱死制动系统运行时，电子控制装置会使电磁阀循环运作，这样既能收回又能释放[FS:PAGE]制动器的压力。当压力释放时，它会释放到液压单元。前部的制动器电路有一个单元。存储器低压存储器，它在低压下存储油液，直到回流泵打开，油液流经制动轮缸进入制动主缸。

Along with the development of the ages, the technique that is nowadays is also gradually perfect, the competition plays more more strong; the operation that list depends the artificial has already can't satisfied with the current manufacturing industry foreground, also can't guarantee the request of the higher quantity and high new the image of the technique business enterprise.

The people see in produce practice, automate brought the tremendous convenience and the product quantities for people up of assurance, also eased the personnel's labor strength, reduce the establishment on the personnel. The target control of the hard realization in many complicated production lines, whole and excellent turn, the best decision etc., well-trained operation work, technical personnel or expert, governor but can judge and operate easily, can acquire the satisfied result. The research target of the artificial intelligence makes use of the calculator exactly to carry out, imitate these intelligences behavior, moderating the work through person's brain and calculators, with the mode that person's machine combine, for resolve the very complicated problem to look for the best path

We come in sight of the control that links after the electric appliances in various situation, that is already the that time generation past, now of after use in the mold a perhaps simple equipments of grass-roots control that the electric appliances can do for the low level only;And the PLC emergence also became the epoch-making topic, adding the vivid software control through a very and stable hardware, making the automation head for the new high tide.

The PLC biggest characteristics lie in: The electrical engineering teacher already no longer electric hardware up too many calculationses of cost, as long as order the importation that the button switch or the importation of the sensors order to link the PLC up can solve problem, pass to output to order the conjunction contact machine or control the start equipments of the big power after the electric appliances, but the exportation equipments direct conjunction of the small power can.

PLC internal containment have the CPU of the CPU, and take to have an I/ O for expand of exterior to connect a people's address and saving machine three big pieces to constitute, CPU core is from an or many is tired to add the machine to constitute, mathematics that they have the logic operation ability, and can read the procedure save the contents of the machine to drive the homologous saving machine and I/ Os to connect after pass the calculation; The I/ O add inner part is tired the input and output system of the machine and exterior link, and deposit the related data into the procedure saving machine or data saving machine; The saving machine can deposit the data that the I/ O input in the saving machine, and in work adjusting to become tired to add the machine and I/ Os to co[FS:PAGE]nnect, saving machine separately saving machine RAM of the procedure saving machine ROM and datas, the ROM can can do deposit of the data permanence in the saving machine, but RAM only for the CPU computes the temporary calculation usage of hour of buffer space.

The PLC anti- interference is very and excellent, our root need not concern its service life and the work situation bad, these all problems have already no longer become the topic that we fail, but stay to our is a concern to come to internal resources of make use of the PLC to strengthen the control ability of the equipments for us, make our equipments more gentle.

PLC language is not we imagine of edit collected materials the language or language of Cs to carry on weaving the distance, but the trapezoid diagram that the adoption is original after the electric appliances to control, make the electrical engineering teacher while weaving to write the procedure very easy comprehended the PLC language, and a lot of non- electricity professional also very quickly know and go deep into to the PLC.

Is PLC one of the advantage above and only, this is also one part that the people comprehend more and easily, in a lot of equipmentses, the people have already no longer hoped to see too many control buttons, they damage not only and easily and produce the artificial error easiest, small is not a main error perhaps you can still accept; But lead even is a fatal error greatly is what we can't is tolerant of. New technique always for bringing more safe and convenient operation for us, make we a lot of problems for face on sweep but light, do you understand the HMI? Says the HMI here you basically not clear what it is, also have no interest understanding, change one inside text explains it into the touch to hold or man-machine interface you knew, it combines with the PLC to our larger space.

HMI the control not only only is reduced the control press button, increase the vivid of the control, more main of it is can sequence of, and at can the change data input to output the feedback with data, control in the temperature curve of imitate but also can keep the manifestation of view to come out. And can write the function help procedure through a plait to provide the help of various what lies in one's power, the one who make operate reduces the otiose error. Currently the HMI factory is also more and more, the function is also more and more strong, the price is also more and more low, the noodles of the usage are wide more and more. The HMI foreground can say that think ° to be good very.

At a lot of situations, the list is is a smooth movement that can't guarantee the equipments by the control of the single machine, but pass the information exchanges of the equipments and equipments to attain the result that we want. For example fore pack and the examination of the empress work preface, we will arrive wrapping information feedback to examine the place, and examine the information of the p[FS:PAGE]lace to also want the feedback to packing. Pass the information share thus to make both the chain connect, becoming a total body, the match of your that thus make is more close, at each other attain to reflect the result that mutually flick.

The PLC correspondence has already come more more body now its value, at the PLC and correspondence between PLCs, can pass the communication of the information and the share of the datas to guarantee that of the equipments moderates mutually, the result that arrive already to repair with each other. Data conversion the adoption RS232 between PLC connect to come to the transmission data, but the RS232 pick up a people and can guarantee 10 meters only of deliver the distance, if in the distance of 1000 meters we can pass the RS485 to carry on the correspondence, the longer distance can pass the MODEL only to carry on deliver.

The PLC data transmission is just to be called a form to it in a piece of and continuous address that the data of the inner part delivers the other party, we, the PLC of the other party passes to read data in the watch to carry on the operation. If the data that data in the watch is a to establish generally, that is just the general data transmission, for example today of oil price rise, I want to deliver the price of the oil price to lose the oil ally on board, that is the share of the data; But take data in the watch for an instruction procedure that controls the PLC, that had the difficulty very much, for example you have to control one  pedestal robot to press the action work that you imagine, you will draw up for it the form that a procedure combine with the data sends out to pass by.

The form that information transport contain single work, the half a work and the difference of a workses .The meaning of the single work also is to say both, a can send out only, but a can receive only, for example a spy he can receive the designation of the superior only, but can't give the superior reply; A work of half is also 2 and can can send out similar to accept the data, but can't send out and accept at the same time, for example when you make a phone call is to can't answer the phone, the other party also; But whole pair works is both can send out and accept the data, and can send out and accept at the same time. Be like the Internet is a typical example.

The process that information transport also has synchronous and different step cent: The data line and the clock lines are synchronous when synchronous meaning lie in sending out the data, is also the data signal and the clock signals to be carry on by the CPU to send out at the same time, this needs to all want the specialized clock signal each other to carry on the transmission and connect to send, and is constrained, the characteristics of this kind of method lies in its speed very quick, but correspond work time of take up the CPU and also want to be long oppositely, at the same time the technique difficulty also very [FS:PAGE]big. Its request lies in can'ting have an error margins in a datas deliver, otherwise the whole piece according to compare the occurrence mistake, this on the hardware is a bigger difficulty. Applied more and more extensive in some appropriative equipmentses, be like the appropriative medical treatment equipments, the numerical signal equipments...etc., in compare the one data deliver, its result is very good.

And the different step is an application the most extensive, this receive benefit in it of technique difficulty is opposite and want to be small, at the same time not need to prepare the specialized clock signal, its characteristics to lie in, its data is partition, the long-lost send out and accept, be the CPU is too busy of time can grind to a stop sex to work, also reduced the difficulty on the hardware, the data throw to lose at the same time opposite want to be little, we can pass the examination of the data to observe whether the data that we send out has the mistake or not, be like strange accidentally the method, tired addition and eight efficacies method etc., can use to helps whether the data that we examine to send out have or not the mistake occurrence, pass the feedback to carry on the discriminator.

A line of transmission of the information contain a string of and combine the cent of: The usual PLC is 8 machines, certainly also having 16 machines. We can be an at the time of sending out the data a send out to the other party, also can be 88 send out the data to the other party, an and 8 differentiationses are also the as that we say to send out the data and combine sends out the data. A speed is more and slowly, but as long as 2 or three lines can solve problem, and can use the telephone line to carry on the long range control. But combine the oscular transmission speed is very quick of, it is a string of oscular of 25600%, occupy the advantage in the short distance, the in view of the fact TTL electricity is even, being limited by the scope of one meter generally, it combine unwell used for the data transmission of the long pull, thus the cost is too expensive.

Under a lot of circumstances we are total to like to adopt the string to combine the conversion chip to carry on deliver, under this kind of circumstance not need us to carry on to depositted the machine to establish too and complicatedly, but carry on the data exchanges through the data transmission instruction directly, but is not a very viable way in the correspondence, because the PLC of the other party must has been wait for your data exportation at the time of sending out the data, it can't do other works.

When you are reading the book, you hear someone knock on door, you stop to start up of affair, open the door and combine to continue with the one who knock on door a dialogue, the telephone of this time rang, you signal hint to connect a telephone, after connecting the telephone through, return overdo come together knock on door to have a conversati[FS:PAGE]on, after dialogue complete, you continue again to see your book, this kind of circumstance we are called the interruption to it, it has the authority, also having sex of have the initiative, the PLC had such function .Its characteristics lie in us and may meet the urgently abrupt affairs in the operation process of the equipments, we want to stop to start immediately up of work, the whereabouts manages the more important affair, this kind of circumstance is we usually meet of, PLC while carry out urgent mission, total will keep the current appearance first, for example the address of the procedure, CPU of tired add the machine data etc., be like to to stick down which the book that we see is when we open the door the page or simply make a mark, because we treat and would still need to continue immediately after book of see the behind. The CPU always does the affair that should do according to our will, but your mistake of give it an affair, it also would be same to do, this we must notice.

The interruption is not only a, sometimes existing jointly with the hour several inside break, break off to have the preferred Class, they will carry out the interruption of the higher Class according to person's request. This kind of breaks off the medium interruption to also became to break off the set. The Class that certainly break off is relevant according to various resources of CPU with internal PLC, also following a heap of capacity size of also relevant fasten.

The contents that break off has a lot of kinds, for example the exterior break off, correspondence in of send out and accept the interruption and settle and the clock that count break off, still have the WDT to reset the interruption etc., they enriched the CPU to respond to the category while handle various business. Speak thus perhaps you can't comprehend the internal structure and operation orders of the interruption completely also, we do a very small example to explain.

Each equipments always will not forget a button, it also is at we meet the urgent circumstance use of, that is nasty to stop the button. When we meet the Human body trouble and surprised circumstances we as long as press it, the machine stops all operations immediately, and wait for processing the over surprised empress recover the operation again.Nasty stop the internal I/ O of the internal CPU of the button conjunction PLC to connect up, be to press button an exterior to trigger signal for CPU, the CPU carries on to the I/ O to examine again, being to confirm to have the exterior to trigger the signal, CPU protection the spot breaks off procedure counts the machine turn the homologous exterior I/ O automatically in the procedure to go to also, be exterior interruption procedure processing complete, the procedure counts the machine to return the main procedure to continue to work.Have 1:00 can what to explain is we generally would nasty stop the button of exterior break off to rise to the tallest Class, thus gua[FS:PAGE]rantee the safety.

When we are work a work piece, giving the PLC a signal, counting PLC inner part the machine add 1 to compute us for a day of workload, a count the machine and can solve problem in brief, certainly they also can keep the data under the condition of dropping the electricity, urging the data not to throw to lose, this is also what we hope earnestly.

The PLC still has the function that the high class counts the machine, being us while accept some datas of high speed, the high speed that here say is the data of the in all aspects tiny second class, for example the bar code scanner is scanning the data continuously, calculating high-speed signal of the data processor DSP etc., we will adopt the high class to count the machine to help we carry on count. It at the PLC carries out the procedure once discover that the high class counts the machine to should of interruption, will let go of the work on the hand immediately. The trapezoid diagram procedure that passes by to weave the distance again explains the high class for us to carry out procedure to count machine would automatic performance to should of work, thus rise the Class that the high class counts the machine to high one Class.

You heard too many this phrases perhaps:" crash", the meaning that is mostly is a workload of CPU to lead greatly, the internal resources shortage etc. the circumstance can't result in procedure circulate. The PLC also has the similar circumstance, there is a watchdog WDT in the inner part of PLC, we can establish time that a procedure of WDT circulate, being to appear the procedure to jump to turn the mistake in the procedure movement process or the procedure is busy, movement time of the procedure exceeds WDT constitution time, the CPU turn but the WDT reset the appearance. The procedure restarts the movement, but will not carry on the breakage to the interruption.

The PLC development has already entered for network ages of correspondence from the mode of the one, and together other works control the net plank and I/ O card planks to carry on the share easily. A state software can pass all se hardwares link, more animation picture of keep the view to carries on the control, and cans pass the Internet to carry on the control in the foreign land, the blast-off that is like the absolute being boat No.5 is to adopt this kind of way to make airship go up the sky.

The development of the higher layer needs our continuous effort to obtain.The PLC emergence has already affected a few persons fully, we also obtained more knowledge and precepts from the top one  experience of the generation, coming to the continuous development  PLC technique, push it toward higher wave tide.

摘自《可编程控制器技术讨论与未来发展》

可编程控制器技术讨论与未来发展

随着时代的发展,当今的技术也日趋完善、竞争愈演愈烈;单靠人工的操作已不能满足于目前的制造业前景,也无法保证更高质量的要求和高新技术企业的形象.

人们在生产实践中看到,自动化给人们带来了极大的便利和产品质[FS:PAGE]量上的保证,同时也减轻了人员的劳动强度,减少了人员上的编制.在许多复杂的生产过程中难以实现的目标控制、整体优化、最佳决策等,熟练的操作工、技术人员或专家、管理者却能够容易判断和操作,可以获得满意的效果.人工智能的研究目标正是利用计算机来实现、模拟这些智能行为,通过人脑与计算机协调工作,以人机结合的模式,为解决十分复杂的问题寻找最佳的途径

我们在各种场合看到了继电器连接的控制，那已经是时代的过去，如今的继电器只能作为低端的基层控制模块或者简单的设备中使用到；而PLC的出现也成为了划时代的主题，通过极其稳定的硬件穿插灵活的软件控制，使得自动化走向了新的高潮。

PLC的最大特点在于：电气工程师已不再电气的硬件上花费太多的心计，只要将按钮开关或感应器的输入点连接到PLC的输入点上就能解决问题，通过输出点连接接触器或继电器来控制大功率的启动设备，而小功率的输出设备直接连接就可以。

PLC的内部包含了具有中央处理器的CPU，并带有外部I/O口扩展的I/O接口地址和存储器三大块组成，CPU的核心是由一个或者多个累加器组成，它们具有逻辑的数学运算能力，并能读取程序存储器的内容通过计算后去驱动相应的存储器和I/O接口；I/O口将内部累加器和外部的输入和输出系统连接起来，并将相关的数据存入程序存储器或者数据存储器中；存储器可以将I/O口输入的数据存入存储器中，并在工作时调转到累加器和I/O接口上，存储器分程序存储器ROM和数据存储器RAM,ROM可以将数据永久的存入存储器中，而RAM只能作为CPU计算时临时计算使用的缓冲空间。

PLC的抗干扰是极其优秀的，我们根本不用去关心它的使用寿命和工作场合的恶劣，这些所有的问题已不再成为我们失败的主题，而留给我们的是关心如何来利用PLC的内部资源为我们加强设备的控制能力，使我们的设备更加的柔性。

PLC的语言并不是我们所想象的汇编语言或C语言来进行编程，而是采用原有的继电器控制的梯形图，使得电气工程师在编写程序时很容易就理解了PLC的语言，而且很多的非电气专业人士也对PLC很快认识并深入。

以上仅仅是PLC的优点之一，这也是人们比较容易理解的一部分，在很多的设备中，人们已不再希望看到太多的控制按钮，它们不但容易损坏而且极易产生人为的失误，小的并不是主要的失误也许你还能够接受；但过大的甚至是致命的失误是我们无法容忍的。新的技术总是为了给我们带来更安全和便捷的操作，使得我们面临的一大堆问题一扫而光，你有了解过HMI吗？这里说HMI你根本不清楚它是什么，也没有兴趣了解，换一个中文把它说明为触摸屏或者人机界面你就知道了，它和PLC的结合给了我们更大的空间。

HMI控制不仅仅是减少了控制按钮，增加控制的灵活性，更主要的它是可顺序性的，而且在能够改变数据输入和数据输出反馈，在温度控制曲线的模拟也能直观的显示出来。并且能够通过编写功能帮助程序来提供各种力所能及的帮助，使得操作者减少不必要的失误。HMI的厂商目前也越来越多，功能也越来越强，价格也越来越低，使用的面越来越广。HMI的前景可以说十分的看好。

在很多场合，单靠单机的控制是无法保证设备的顺畅运行，而通过设备与设备的信息交流达到我们想要的效果。比如在前包装和后工序的检测，我们就要将包装的信息反馈到检测处，而检测处的信息也要反馈到包装来。这样通过信息共享来使得两者之间链接起来，形成一个共体，从而使的两者间的配合更加的紧密，在彼此间达到映影相挥的效果。

PLC的通信已经愈来愈体现它的价值，在PLC与PLC之间的通信，能够通过信息的沟通和数据的共享来保证设备之间的相互协调，已达到互补的效果。PLC之间的数据转换采用RS232接口来传送数据，而RS232接口只能保证10米的传输距离，如果在1000米的距离内我们可以通[FS:PAGE]过RS485来进行通信，更长的距离只能通过MODEL来进行传输。

PLC的数据传送只是将内部的数据传送到对方的一块连续的地址中，我们把它称为一个表，对方的PLC通过读取表中的数据来进行操作。如果表中的数据是一个一般设置的数据的话，那只是一般的数据传送，比如今天的油价上升了，我要把油价的价格传送到所有的输油机上，那就是数据的共享；而当表中的数据是一段控制PLC的指令程序，那就很有难度了，比如你要控制一台机器人来按你想象的动作工作，你会给它编制一段程序并以数据的形式发送过去。

信息输送的形式有单工位、半双工位和全双工位的分别。单工位的意义也就是说两者之间，一个只能发送，而一个只能接收，比如一个特务他只能接收上司的指示，而无法给上司回复；半双工位也就是两个能都能发送和接受数据，但不能同时发送和接受，比如你打电话时是不能接电话,对方也一样；而全双工位是两者之间都能发送和接受数据，并可同时发送和接受。像互联网就是典型的例子。

信息输送的过程也有同步和异步之分：同步的意义在于发送数据时数据线和时钟线是同步的，也就是数据信号和时钟信号同时由CPU进行发送，这需要彼此都要专门的时钟信号来进行传送和接送，并且是强制性的，这种方法的特点在于它的速度极快、但相应占用CPU的工作时间也相对的要长、同时技术难度也非常的大。它的要求在于在一帧的数据传送中不能有一位的误差，不然的话整个数据将发生错误，这在硬件上是一个比较大的难度。在一些专用的设备中应用的越来越广泛，像专用的医疗设备、数字信号设备等，在比较单一数据的传输中，它的效果非常的好。

而异步是应用范围最广泛的，这得益于它的技术难度相对要小、同时不需要配制专门的时钟信号、它的特点在于，它的数据是间隔性的，离散性的发送和接受，当CPU太忙的时候可以停顿性去工作，在硬件上也减少了难度，同时数据的丢失相对要少，我们可以通过数据的检测来观察我们发送的数据是否有错误，像奇偶法、累加法和八位效验法等，都可以用来帮助我们检测发送的数据是否有错误发生，通过反馈来进行辨别。

信息的传送口线有串口和并口之分：通常的PLC是8位机，当然也有16位机。我们在发送数据的时候可以是一位一位的发送给对方，也可以8位8位的将数据发送到对方，一位和8位区别也就是我们所说的串口发送数据和并口发送数据。串口速度比较慢，但只要两条或者三条口线就能解决问题，并能借用电话线来进行远程控制。而并口的传送速度是极快的，它是串口的256倍，在短距离占有优势，由于是TTL电平，一般限于1米的范围，它并不适用于长距离的数据传送，这样成本太昂贵了。

很多的情况下我们总喜欢采用串并转换芯片来进行传输，这种情况下不需要我们进行过于复杂的寄存器设置了，而直接通过数据传送指令进行数据交流，但在通信中并不是一个十分可行的办法，因为在发送数据的时候对方的PLC必须一直等待你的数据输出，它不能去做其他的工作。

当你在看书的时候，你听到有人敲门、你停下手上的事情、去打开门、并同敲门者对话、这个时候电话响了、你示意接个电话、在接完电话后、回过头来同敲门者继续对话、对话完毕后、你再继续看你的书，这种情况我们把它称为中断，它具有权威性，也具有优先性，PLC具备了这样的功能。它的特点在于我们在设备的操作过程中可能会遇到紧急的突发事件，我们要立刻的停下手上的工作，去处理更重要的事情，这种情况是我们经常所遇到的，PLC在去执行紧急的任务时，总会先保存目前的状态，比如程序的地址，CPU的累加器数据等，就像我们去开门时要记下我们看的书在第几页了或者干脆作个记号，因为我们待会还要继续接着看后面的书。CPU总是按照我们的意愿去做应该做的事情，但你错误的给它一件事情，它也[FS:PAGE]会同样的去做，这一点我们必须注意。

中断并不是只有一个，有时会同时存在几个中断，中断具有优先的级别，他们会根据人的要求去执行更高级别的中断。这种中断中的中断也就形成了中断嵌套。当然中断的级别根据各种PLC内部CPU的资源有关，同时也跟堆栈的容量大小也有关系。

中断的内容有很多种，比如外部中断、通信中的发送和接受中断、定时和计数的时钟中断、还有WDT复位中断等，它们丰富了CPU在处理各种事务时响应种类。这样讲也许你并不能完全理解中断的内部结构和操作顺序，我们做一个小小的例子来说明.

每一个设备总是不会忘记有一个按钮，它也是在我们遇到紧急情况时使用的，那就是急停按钮。当我们遇到人身事故和意外情况时我们只要按下它，机器立即停止所有的操作，并等待处理完意外后再恢复操作。急停按钮连接PLC内部CPU的内部I/O接口上，当按钮给CPU一个外部触发信号时，CPU对I/O进行再次检测，当确认有外部触发信号时，CPU保护现场并将程序计数器自动转到相应的外部I/O中断程序中去，当外部中断程序处理完毕，程序计数器返回到主程序继续工作。有一点可以说明的是我们一般会把急停按钮的外部中断升至最高级别，从而保证安全。

当我们在工作完一个工件时，给PLC一个信号，将PLC的内部计数器加1来计算我们一天的工作量时，一个简单的计数器能解决问题，当然它们也能够在掉电的情况下保持数据，促使数据不丢失，这也是我们所渴望的。

PLC还具有高级计数器的功能，当我们在接受一些高速的数据时，这里所说的高速是在在微秒级的数据，比如条码扫描机在不断的扫描数据，数据处理器DSP计算的高速信号等，我们就要采用到高级计数器来帮助我们进行计数。它在PLC执行程序时一旦发现高级计数器对应的中断，就会立即放下手上的工作。经过再次编程的梯形图程序说明我们在执行程序时高级计数器会自动的执行对应的工作，从而将高级计数器的级别升至高一级别。

你也许听过太多的这个词:“死机”，大致的意思是CPU工作量过大，内部资源不足等情况造成程序无法运行。PLC也有类似的情况，在PLC内部有一个看门狗WDT，我们可以设置WDT一个程序运行的时间，当程序运行过程中出现程序跳转错误时或者程序繁忙时，程序的运行时间超过WDT的设置时间，CPU转而WDT复位状态。程序重新开始运行，但对中断不会进行破坏。

PLC的发展已经从单一的模式进入了通信的网络时代，并同其它的工控网板和I/O卡板轻易的进行共享。组态软件可以将所有的这些硬件连接起来，通过更直观的动画图片来进行控制，并可以通过互联网在异地进行控制，像神舟五号的发射就是采用这种办法来使飞船升空。

更高层次的发展需要我们不断的努力来取得。PLC的出现已经足足影响了几代人，我们也从上一辈的经验中获取了更多的知识和教训，来不断的发展PLC技术，将它推向更高浪潮。

致谢

在本次毕业设计以及论文编写过程中，我得到了公司的大力支持。从项目的选定、和理性分析到最后的论文编排，胡老师都给了我许多指导和帮助。同时也感谢我的指导教师朱文虎老师，在设计项目的开始阶段，也是我最迷茫的阶段，朱老师给了我跟多方向上的建议和指导，使我明确了设计目的。毕业设计是一个系统化的工程，在这个过程中我遇到了很多无法靠自己能力以及知识储备来解决的问题，尽管付出了很多努力，但是仍然无法没有明显的进展，这使我明白了协同工作的重要性。一个人的知识面永远都是有限的，在接触到一个全新的领域时，都会遇到很多棘手的问题，这是就要不断地想别人请教和咨询。这次的毕业设计不进是我了解了很多新的知识，更重要的是我检索和获取知识的能力的到了很大的提高，这跟老师们给我的指导也是分不开的。

最后，还要感谢江西理工大学以及机电工程学院学院的所有老师在这[FS:PAGE]大学期间给我的培养。不仅使我学到了很多新知识，更重要的是，使我建立起了一套完整的科学思考观，正是有了这样科学的分析和思考问题的方式，才能使我解决毕业设计中遇到的一系列问题，同时这在我以后的生活、学习和工作中也将起到举足轻重的作用。

You Bo Ding Liang Xu Jiazhong

（Harbin University of Science and Technology, Harbin 150080 China）

Abstract: In this paper, a kind of intelligent low temperature protecting device with theft proof function for cars is presented from the aspects of both hardware structure and software design. By keeping the environment temperature suitable for the engine to run, it solves a good many problems for cars when cars are kept under low temperature circumstances. The temperature collecting circuit with DS1820 digital sensor, running lamp control circuit with a 555 integrated timer, flow chart of main control program and so on, are all introduced particularly.

Keywords: DS1820 sensor; 555 oscillating circuit; Low temperature protecting device; Watchdog.

1 Introduction

If cars are remained off for a long while under cold circumstances, the lubricant viscosity of engine’s drive system and electrolyte viscosity of battery will become larger, volatility of gas will be weaker and oil film will fall off, so that a lot of problems may be brought on because of low temperature, such as the car is difficult to start and hard to run quickly at the beginning, its assembly especially the engine wears out severely, the battery’s voltage is lower.

The intelligent low temperature protecting device with theft proof function for cars is developed to solve the problems brought forward above. Not only can it resolve the problems by keeping the environment temperature suitable for the engine to run, but also it can guard against theft independently and can be compatible with additional theft proof device installed by users themselves. The devices have been used on cars of some cities in China, and they are proved to be convenient, economical and useful.

2 Hardware Structure

The hardware structure diagram of low temperature protecting device for cars is shown in Fig.1, which is mainly composed of CPU, external interface circuit, voltage stabilization module, display module, auxiliary control circuit, 555 oscillating circuit, watch dog circuit, key input module, etc.

The system adopts 89S51 SCM produced by ATMEL Corporation as its CPU. The external interface circuit includes some relays, sensors, switches and a buzzer. The DS1820 digital temperature sensor made by Dallas Corporation, three-terminal vibration sensor with adjustable precision, negative burst switch on the door and a buzzer constitute external theftproof circuit; the level of “On” wire, startup wire, running lamp wire and the theftproof stalled by users are controlled through JD1914 relays; and the gas induction switch is applied to detect whether the engine is running or not. The +12V wire of car’s battery connects to voltage stabilization module through a relay on board, with the help of which, the negative burst switch on the door can cut off power supply to the system while the car’s door is opened, ensuring tha[FS:PAGE]t the engine is not running while someone is going into the car. In order to obtain a stable +5V voltage and avoid interference from external components, the LC filter circuit are used to filter voltage waves, and double 7805 power supply method is adopted. The display module includes three 8-segment LED displays and a three-color LED lamp, displaying temperature data and work state of the system, and users can set the value of TL (the lowest temperature to start the engine) and TH (the highest temperature to stop the engine) between -55 to 125 centigrade degrees with the help of it and the key input module. With the ability of level conversion and avoiding reverse voltage, the auxiliary control circuit can receive external signals and transmit them to CPU after conversion, or convert the output signals from CPU to control the external components. The specific microprocessor control chip MAX813L produced by MAXIM Corporation is used as the core of watch dog circuit, which can reset system while power is on or there is something wrong with the system, advancing its credibility and veracity.

Fig.1 Hardware Structure Diagram

(1) Circuit of DS1820

DS1820 digital temperature sensor uses on-board patent technology and all of the components such as the temperature sensor and conversion circuit are integrated and encapsulated like a triode, with a measuring range of -55 to +125℃ in 0.5℃ increments. Temperature is represented in the DS1820 in terms of a 0.5℃ LSB, with MSB as the sign bit. The measuring result will be transmitted to P3.0 port of 89S51 serially over the 1–wire interface through a 120Ω resistor, with a 2KΩ pull-up resistor connecting to it. Fig.2 shows how the three pins of DS1820 are connected. The memory of DS1820 consists of a scratchpad RAM and a nonvolatile, electrically erasable (E2) RAM, which stores the high and low temperature triggers TH and TL. Data is first written to the scratchpad where it can be read back. After the data has been verified, a copy scratchpad command will transfer the data to the E2RAM. The scratchpad is composed of eight bytes memory information with the third byte TH and the fourth one TL.

(2) Voltage stabilization module

The double 7805 method is shown in Fig.2; power of the system is supplied by a UA7805C and a KA78L05Z encapsulated like triodes is applied to supply power for external sensors such as the temperature sensor DS1820 and precision adjustable vibration sensor. The voltage of cars’ battery is not stable, for example, while the engine is start up, the voltage is about 10V, 2V less than that of usual, and the output voltage from 7805 will then change a lot correspondingly. In order to avoid the sharp change at the output port of 7805, it is necessary to use LC filter circuit, including a large polarity capacitor of 1000uF and an inductor; a 0.1uF capacitor is also used to avoid high frequency interference. The voltage output ports of 7805 connect to the ground through some 10uF capacito[FS:PAGE]rs to keep the voltage more stable. The ctrl1 and ctrl2 signals connecting to HJR-4102-12V relay are used to realize the protecting ability of negative burst by the door; if the door is opened, the power input port will be disconnected to the diode, so power supply of the system is cut off, unless the door is shut up again.

Fig.2 Voltage stabilization module

(3) Control circuit of running lamp

While the engine is running to keep its temperature higher than TL, the running lamp will be on and off alternately. The running lamp control circuit diagram is shown in Fig.3. When the engine is running, the CONTROL port will be set to high level; the 555 integrated timer will be electrified and begin to work. At first, C1 is charged through HR2, HR3 and D12, and when the voltage of C1 is higher than 2/3Vcc, Q port will be set to high level, making the external relay electrify and the running lamp be on. At the same time, the internal discharging transistor is on; capacitor C1 will discharge through D1 and HR4. When the voltage value of C1 declines to lower than 1/3Vcc, Q port will be reset and the running lamp will be off. The internal discharging transistor is cut off and capacitor C1 will be charged again. Repeating like this, a rectangular wave is obtained at port Q, and the running lamp will be on and off alternately, indicating that the engine is running.

Fig.3 Running Lamp Control Circuit Diagram

The pulse width of the first temporary steady statetp1, i.e. the charging time of capacitor C1 is:

tp1≈(HR2+ HR3)×C1×Ln2=0.7(HR2+ HR3)C

And the pulse width of the second temporary steady state tp2 , i.e. the discharging time of capacitor C1 is:

tp2 ≈ HR4×C1× Ln2 = 0.7HR4×C1

The duty ratio is:

（4）Watchdog circuit

Fig. 4 Watchdog Circuit

As shown in Fig.4, the watchdog circuit

used MAX813L produced by MAXIM Corporation of America as its core, which can improve the reliability of the system by resuming it to the usual running state when there is something wrong with the program. While running, the program continuously generates low level pulses to MAX813L through P3.7 port with a time interval less than 1.6 seconds; if the program runs improperly and the SCM can’t send another low level pulse to the WDI port beyond 1.6 seconds, the RST port will send a reset signal to 89S51, making the program run from the initial state.

3 Software Design 

The software mainly consists of main control module, keystroke interrupt serving subprogram, temperature collecting and processing module and display module.

The main control module is kernel part of the software, the flowchart of which is shown in Fig.5. At the beginning, parameters are initialized; the value of TH and TL are read from DS1820 to 89S51’s RAM. And then, data corresponding to the current motor temperature are collected and calculated to display and compare with TH/TL. If it is lower than TL, the car will be powered on with +12V voltage from he battery, after several[FS:PAGE] seconds, the engine will be started up with a +12V pulse, the time of which is determined by the selecting switches that work like a 3-8 encoder; from 0.2s to 1.4s in 0.2s increments, set up by the sales men according to the type of cars. After 15s, the program will detect the gas inducting switch to determine whether the engine is run properly or not. If the car can’t run properly, the engine will be started up again, and the process will not stop until the +12V pulse for starting up the car has been generated for six times, when the program considers that there is something wrong with the car and then alarm occurs. Else, the startup flag will be set to 1; the program will detect gas inducting switch and display current motor temperature. If the temperature is higher than TH, the +12V voltage to the car will be cut off, the startup flag be set to 0 and the engine stop; and if the engine has stopped but the startup flag is still 1, the program will consider that some malfunction occurs to the car, such as the gas has been exhausted, then it will stop the engine and give an alarm. While the engine is running, the additional theft proof device should be shut down to avoid alarm, but the theft proof part of

Fig.5 The main control module is kernel part of the software

low temperature protecting device is still work. Users should adjust the

precision of vibration sensor beforehand by modulating resistance of the adjustable resistor, ensuring that low temperature protecting device will not alarm while the engine is running to heat up, but will give an alarm if there is some additional vibration. If the door is opened illegally or the vibration sensor carried by the system is triggered because of additional vibration, the engine will be stopped immediately, the buzzer will alarm and the additional theft proof will be connected again.

(2)The keystroke interrupt serving

subprogram, the flow chart of which is shown in Fig.6, deals with keystroke information of three keys (key_1, key_2 and key_3). The function of setting the lowest temperature (TL) to stop the engine, the highest temperature (TH) to start the engine and clearing the alarm information are realized by setting flag bit (mode-flag) to make different use of the first key. When key_1 is pressed for the first time, if the alarm flag is 1, the program will stop buzzer alarm and turn off the three-color LED lamp, else, it will set mode-flag to 1 which means that the user want to set TH, and wait until pressed, with key_2 meaning 1℃ increment and key_3 meaning 1℃ decrement. It will set mode-flag to 2 the second times to press key_1, indicating that TL will be set and it will exit the interrupt serving subprogram and memorize the value of TH and TL to DS1820 the third time pressing key_1.

Fig.6 Flow Chart of Keystroke serving subprogram anyone of the three keys is

(3)The temperature collecting and processing module is used to obtain data corresponding to present temperature of the engine[FS:PAGE], convert them to make preparation for display. The temperature collecting and processing flowchart is shown in Fig.7. The function for skipping ROM, reading temperature value from the scratchpad and so on are realized with the help of writing command words to DS1820, which can be known by referring to Dallas Semiconductor Book of DS1820.

Fig.7 Temperature Collecting and Processing Flow Chart

(4)The display module can display temperature and work state of the system. Usually, the value of current engine temperature is displayed and the LED lamp is off. When the engine is start up by a +12V pulse, the LED lights in red color; it will light in orange color when giving an alarm, and will light in green color for a little while after the engine finishes the heating up process. If the user is setting TH, the upper left segment of the first 8-segment LED will light and the lower left segment of it will light while setting TL.

4 Conclusion

This system has already been used in the cars of some cities in China such as Harbin and Daqing. Experiments and feedback of the users show that it is convenient to use low temperature protecting device, working stably and creditably. If the value of TH and LH is respectively set to 60℃ and -5℃, the engine will be started to run about 6 minutes in every 2.5 hours and only about 0.05～0.2 liters of gas are consumed per night.

Reference

[1] Li Chuncheng Chen Anyu. The Influence on Cars of Low Temperature Circumstances and Resolving Methods. Special Cars. 2003, 2

[2] Dallas Semiconductor data book. Dallas Semiconductor Corporation, 1995

[3] Qin Zenghuang. Electronic Technology. Beijing: Higher Education Press, 2001

[4] Liu Guoyong Introduction of. Microprocessor Watchdog MAX813L. Foreign Electronic Devices. 1997, 6

[5]Zhang Junmo. MCU Intermediate Tutorial. Beijing: BUAA Press, 2002, 8 Author Biographies

中文翻译

汽车防盗功能下的低温保护设备的开发

尤波 丁亮 徐稼忠

（哈尔滨科技大学，中国哈尔滨150080）

摘要：在这篇文章中，从硬件结构和软件设计两方面介绍一种具有防盗功能的智能型汽车低温保护设备。当汽车保持在低的温度环境之下的时候，保持引擎工作的合适的环境温度，它能为汽车解决很多的问题。用 DS1820 数字传感器电路收集温度, 一个 555定时器构成运行放大控制电路, 主要控制计画的流程图等等,详细地全部被介绍。

关键词：DS1820 传感应器；555振荡电路；低温保护设备；看门狗

引言

如果汽车被保持在寒冷的环境之下很长时间,引擎的驾驶系统的润滑黏性和电池的电解物黏性将会变得比较大的, 汽油的挥发性将会是比较弱的而且润滑下降 , 所以低温可能带来许多问题, 例如汽车难以启动并且开始时很难加速, 特别是汽车引擎零件的磨损严重, 电池的电压是比较低的。

开发具有防盗功能的智能型汽车低温保护装置能解决上面所带来的问题。不但能解决引擎合适的工作环境温度保持问题 , 而且它能独立地防止窃盗并且能与被使用者安装的另外防盗装置相容。装置已经在中国的一些城市的汽车上被用，而且证明他们是方便的、经济的和有用的。

2. 硬件结构

汽车低温保护设备的硬件结构的图形如图1所示,它主要组成由处理器，外部的独立电路，电压稳定组件，显示组件,帮助者控制线路， 555振动电路路，看[FS:PAGE]门狗电路，主要输入组件, 等等。

处理器系统采用 ATMEL 公司生产的 89S51 SCM 。 外部的独立电路包括一些继电器，传感器，开关和一个蜂鸣器。DS1820 数字温度传感器是达拉斯公司制造,三端可调的精密终端的震动传感器 , 在门上的阴极脉冲开关和一个蜂鸣器构成外部的防盗电线路；“ON” 的电平线路,启始线路, 运行放大线路和使用者经过 JD1914 组件控制关闭防盗设备； 而且汽油感应开关被应用于发现引擎是否正在运行。汽车的电池 +12 V 电线在车上经过一个替续器连接到电压稳定组件,当汽车的门被打开的时候，用于帮助,在门上的阴极脉冲开关能切断电力补给系统, 确保当某人进入汽车的时候，引擎不能运行。为了要获得一个稳定的+5 V 电压而且避免来自外部的因素的干扰， LC 滤波器线路用来过滤电压波 , 和采用两个7805 电压提供的方法。显示部分包括3个8段LED显示器和一个三色LED发光灯,显示温度数据和系统的工作状态, 而且使用者能够对他设定 TL(引擎启动最低的温度) 和 TH(引擎停止最高的温度) 在摄氏温度-55到125之间和键盘输入组件。带有电平转变和避免反向电压的能力, 辅助控制电路在转变接受到的外部的信号之后把信号送到处理器, 或转换从处理器输出的控制外部的电路的信号。MAXIM公司生产的 MAX813L特殊的微处理器控制芯片被当作看门狗电路的核心, 当电源打开后或系统有一些问题的时候，能重新设定系统,提高它的可靠性和精确性。

图1 硬件结构图

DS1820 电路

DS1820 数传温度感应器使用平板专利技术并且所有的部份 , 像温度感应器和转换电路是完整的密封的像一个三极真空管, 在测量范围 -55 到  +125 ℃增量为0.5℃。温度被根据 0.5 ℃ LSB 在 DS1820 表现,用 MSB 作为信号比特。测定的结果将会连续地被传送到 89S51 的 P3.0 口在1号线接口通过一个 120 Ω电阻,与 2 K Ω拉升高电阻与它连接。图2所示的是DS1820的三个管脚如何连接。

DS1820 的储存器包括一个随机程序存取储存器和一个不可擦除存储器,电可消除的 (E2) 随机存取储存器的高低温线是 TH 和 TL 。 数据首先被写到随机程序存取储存器，它还能被读出来 。在数据被校准之后,一个副本程序指令将会把数据转移到 E2RAM 。 由第三位表示 TH 和第四位是TL的八位记忆数据组成的程序。

稳压模块

图2显示的是两个 7805个方法 ;像三极管一样封装的UA7805C 和KA78L05Z 组成电源系统向外部的感应器供应电能, 像是温度感应器 DS1820 和精密可调整震动感应器。汽车的电池电压是不稳定,举例来说，当引擎启动时候,电压是大约10 V , 比平常的低 2 V , 和从 7805 输出的电压对应的改变将会很多。为了避免7805输口电压发生锐利的变化 ,必需使用 LC 过滤器线路是的,包括一个 1000 uF 的电解电容器和一个电感线圈; 一个 0.1 uF 电容器也用来避免高的频率干扰。7805的电压输出口经过一些 10 uF 电容器对地连接用于保存电压较大的稳定性。ctrl1 和 ctrl2的信号 连接到 HJR-4102-12 V 的连接器通过警戎门上的阴极脉冲的保护能力; 如果门被打开,电源输入端将会被分离通过二极管，因此，切断电源补给系统, 除非门再一次被关上。

图 2 稳压模块

(3) 放大管控制线路

在引擎运转的时候能保持它的温度比 TL 高，放大管将会交替开关。放大管控制线路图如图3所示。当引擎运转的时候,控制端将会被设定成高的电平; 555 定时器将会被通电并且开始工作。首先， C1 经过 HR2 ， HR3 和 D12 被充电，而且当 C1 的电压是比 2/3 Vcc 高的时候,Q 端将会被设定成高电平, 使外部的继电器通电和放大管开通。 同时，内部的晶体三极管道通放电; 电容器 C1 将会通过 D1 和 HR4放电 。当 C1 的电压值降到比 1/3 Vcc 低的的时候,Q 端将会被重新设定，放大管将会关闭。内部的晶体放电三极管会关闭[FS:PAGE]，而且电容器 C1 将会在再一次被充电。 像这重复, 一个矩形波在Q 端被获得，而且放大晶体管将会交替地开通,指出引擎正在运转。

图 3 放大管控制电路图

第一个暂时的稳定的状态的脉冲宽度, 也就是电容器 C1的充电时间是: 

tp1≈(HR2+ HR3)×C1×Ln2=0.7(HR2+ HR3)C

而第二个暂时稳定状态的脉冲宽度, 也就是，电容器 C1 放电时间是:

tp2 ≈ HR4×C1× Ln2 = 0.7HR4×C1

占空比是：

（4）看门狗电路

图4看门狗电路

如 图.4 所示，看门狗电路用美国的MAXIM公司生产的 MAX813L作为它的核心, 当程序有一些错误的时候，通过复位它能改善系统的可靠性达到正常的运转状态。当运行时候,程序不断地经过 P3.7 口 向 MAX813L 产生一个间隔时间低于 1.6 秒的低电平脉冲; 如果程序运行不正常，SCM超过 1.6 秒不能向WDI 口传送另外的一个低电平脉冲到,RST 口将会送一个复位信号给 89S51,使程序从原始状态运行。

3 软件设计

软件主要地有主控制组件,按键服务中断子程序，温度采集和处理组件和显示组件的。

(1)主要的控制组件是软件的核心部份，如图.5 显示的流程表。在开始，叁数被设定初值; TH 和 TL 的值从 DS1820 写入到 89S51's 随机存取储存器。然后,收集与现在的发动机温度相对应的数据而且计算显示并且与 TH/TL 相比较。如果它比 TL 低的, 汽车将会使用由于 +12 V 的电池电压供能, 在好几秒之后，引擎将会用+12 V 脉冲启动 ，被选择开关决定工作的时候像一个 3-8 编码器；按每 0.2 秒的增量从 0.2 秒到 1.4 秒, 被销售员依照汽车的类型设立。 在 15 秒之后，程序将会检测汽油引导开关来决定引擎是否正常地运行。如果汽车不能正常运行, 引擎将会被再次启动，而且程序直到汽车在 +12 V 脉冲下六次发热启动才停止, 当程序检测汽车有故障到的时候然就会报警。此外，启始标志将会被设定成 1; 程序将会发现汽油引导开关而且显示现在的发动机温度。如

图 5 主控部分流程图

果温度比 TH 高的,汽车的 +12 V 电压将会被切断, 启动标志被设定在 0 ，引擎也会停止; 而且如果引擎已经停止，但是启动标志仍然是 1, 程序将会认为汽车发生一些故障, 像汽油已经被用尽,然后它将会停止引擎而且发出警报。当引擎运转时，应该关闭额外的防盗装置以避免报警，但是低温度的保护装置中的防盗部份仍然是工作的。使用者应该预先通过调整可调的电阻来调整震动感应器的精确度,确保引擎运转加热时低温保护装置将不不会报警， 但是如果有额外的震动是应该给出警报。如果门非法地被打开，或者因为震动感应器带来的额外震动被系统触发,引擎将会立刻被停止,蜂鸣器将会报警，而且另外的防盗装置将会在再一次被连接。

按键中断服务子程序，如图.6 所示的流程图，来处理三个按键的数据(key_1 ， key_2 和 key_3) 。实现设定引擎停止最低的温度 (TL) ,引擎启动的最高的温度 (TH) 和清处报警数据的功能，由设定标志点 (模态-标志) 去设置不同使用键。当第一次按下key_1的时候，如果报警标志是1, 程序将会停止蜂鸣报警而且关掉三色LED晶体管,此外，它被设定模态- 标志到1 意味着使用者想要设定 TH 和等候直到被压下,key_2意味着 1℃增量和 key_3 意谓 1℃的渐减 。资讯科技将会设定模态- 标志到 2 第二次压 key_1, 指出 TL 将会被设定，第三次压迫 key_1将会退出中断服务子程序并且通过 DS1820 存储的 TH 和 TL 的值。

图 6 三键的服务子程序的流程图

(3)温度收集和处理组件通常被用来获得符合目前引擎的温度数据,转换他们为显示准备。图.7所示的是温度收集和处理的流程图。 跳读ROM 的功能, 从存储器读温度实现写指令字给 DS1820 的帮忙,这能 DS1820 的达拉斯半导体书被告知道。

图 7 温度收集和处理流程图

(4)显示组件能显示温度和操[FS:PAGE]作系统的状态。 通常，现在引擎温度的值被显示，而且关闭LED发光灯。当引擎用 +12 V 脉冲启动时,LED发光管亮红色的光;当有警报的时候，LED发光管亮橘黄色的光，在引擎完成发热之后将会LED发光管亮绿色的光。如果使用者正在设定 TH,第一个 8段LED数码管的左边上面的部分亮，而且当设定 TL 的时候，它的左边下面部分将会亮。

4. 结论

中国的一些城市的汽车已经使用这一个系统, 像哈尔滨和大庆 。 使用者的实验和回应表示使用低温度保护装置很方便，工作稳定可靠。如果 TH 和 LH 的值分别地被设定成 60 ℃和 -5 ℃, 引擎将会在每个 2.5 小时被启动运转大约 6 分钟和每一夜晚仅仅大约耗损汽油0.05 ～ 0.2 公升。

High-speed machining is an advanced manufacturing technology, different from the traditional processing methods. The spindle speed, cutting feed rate, cutting a small amount of units within the time of removal of material has increased three to six times. With high efficiency, high precision and high quality surface as the basic characteristics of the automobile industry, aerospace, mold manufacturing and instrumentation industry, such as access to a wide range of applications, has made significant economic benefits, is the contemporary importance of advanced manufacturing technology. For a long time, people die on the processing has been using a grinding or milling EDM (EDM) processing, grinding, polishing methods. Although the high hardness of the EDM machine parts, but the lower the productivity of its application is limited. With the development of high-speed processing technology, used to replace high-speed cutting, grinding and polishing process to die processing has become possible. To shorten the processing cycle, processing and reliable quality assurance, lower processing costs.

1 One of the advantages of high-speed machining

High-speed machining as a die-efficient manufacturing, high-quality, low power consumption in an advanced manufacturing technology. In conventional machining in a series of problems has plagued by high-speed machining of the application have been resolved.

1.1 Increase productivity
High-speed cutting of the spindle speed, feed rate compared withtraditional machining, in the nature of the leap, the metal removal rate increased 30 percent to 40 percent, cutting force reduced by 30 percent, the cutting tool life increased by 70% . Hardened parts can be processed, a fixture in many parts to be completed rough, semi-finishing and fine, and all other processes, the complex can reach parts of the surface quality requirements, thus increasing the processing productivity and competitiveness of products in the market.

1.2 Improve processing accuracy and surface quality
High-speed machines generally have high rigidity and precision, and other characteristics, processing, cutting the depth of small, fast and feed, cutting force low, the workpiece to reduce heat distortion, and high precision machining, surface roughness small. Milling will be no high-speed processing and milling marks the surface so that the parts greatly enhance the quality of the surface. Processing Aluminum when up Ra0.40.6um, pieces of steel processing at up to Ra0.2 ~ 0.4um.

1.3 Cutting reduce the heat
Because the main axis milling machine high-speed rotation, cutting a shallow cutting, and feed very quickly, and the blade length of the workpiece contacts and contact time is very short, a decrease of blades and parts of the heat conduction. High-speed cutting by dry milling or oil cooked up absolute (mist) lubrication system, to avoid the traditional processing tool in contact with the workpiece and a lot of shortcomings to ensure [FS:PAGE]that the tool is not high temperature under the conditions of work, extended tool life.

1.4 This is conducive to processing thin-walled parts

High-speed cutting of small cutting force, a higher degree of stability, Machinable with high-quality employees compared to the company may be very good, but other than the company's employees may Suanbu Le outstanding work performance. For our China practice, we use the models to determine the method of staff training needs are simple and effective. This study models can be an external object, it can also be a combination of internal and external. We must first clear strategy for the development of enterprises. Through the internal and external business environment and organizational resources, such as analysis, the future development of a clear business goals and operational priorities. According to the business development strategy can be compared to find the business models, through a comparative analysis of the finalization of business models. In determining business models, a, is the understanding of its development strategy, or its market share and market growth rate, or the staff of the situation, and so on, according to the companies to determine the actual situation. As enterprises in different period of development, its focus is different, which means that enterprises need to invest the manpower and financial resources the focus is different. So in a certain period of time, enterprises should accurately selected their business models compared with the departments and posts, so more practical significance, because the business models are not always good, but to compare some aspects did not have much practical significance, Furthermore This can more fully concentrate on the business use of limited resources. Identify business models, and then take the enterprise of the corresponding departments and staff with the business models for comparison, the two can be found in the performance gap, a comparative analysis to find reasons, in accordance with this business reality, the final identification of training needs. The cost of training is needed, if not through an effective way to determine whether companies need to train and the training of the way, but blind to training, such training is difficult to achieve the desired results. A comparison only difference between this model is simple and practical training.

1.5 Can be part of some alternative technology, such as EDM, grinding high intensity and high hardness processing

High-speed cutting a major feature of high-speed cutting machine has the hardness of HRC60 parts. With the use of coated carbide cutter mold processing, directly to the installation of a hardened tool steel processing forming, effectively avoid the installation of several parts of the fixture error and improve the parts of the geometric location accuracy. In the mold of traditional processing, heat treatment hardening of the workpiece required EDM, high-speed machining repla[FS:PAGE]ce the traditional method of cutting the processing, manufacturing process possible to omit die in EDM, simplifying the processing technology and investment costs .
High-speed milling in the precincts of CNC machine tools, or for processing centre, also in the installation of high-speed spindle on the general machine tools. The latter not only has the processing capacity of general machine tools, but also for high-speed milling, a decrease of investment in equipment, machine tools increased flexibility. Cutting high-speed processing can improve the efficiency, quality improvement, streamline processes, investment and machine tool investment and maintenance costs rise, but comprehensive, can significantly increase economic efficiency.

2 High-speed milling

High-speed milling the main technical high-speed cutting technology is cutting the development direction of one of it with CNC technology, microelectronic technology, new materials and new technology, such as technology development to a higher level. High-speed machine tools and high-speed tool to achieve high-speed cutting is the prerequisite and basic conditions, in high-speed machining in the performance of high-speed machine tool material of choice and there are strict requirements.
2.1 High-speed milling machine in order to achieve high-speed machining

General use of highly flexible high-speed CNC machine tools, machining centers, and some use a dedicated high-speed milling, drilling. At the same time a high-speed machine tool spindle system and high-speed feeding system, high stiffness of the main characteristics of high-precision targeting and high-precision interpolation functions, especially high-precision arc interpolation function. High-speed machining systems of the machine a higher demand, mainly in the following areas:

General use of highly flexible high-speed CNC machine tools, machining centers, and some use a dedicated high-speed milling, drilling. At the same time a high-speed machine tool spindle system and high-speed feeding system, high stiffness of the main characteristics of high-precision targeting and high-precision interpolation functions, especially high-precision arc interpolation function. High-speed machining systems of the machine a higher demand, mainly in the following areas:
High-speed milling machine must have a high-speed spindle, the spindle speed is generally 10000 ~ 100000 m / min, power greater than 15 kW. But also with rapid speed or in designated spots fast-stopping performance. The main axial space not more than 0 .0 0 0 2 m m. Often using high-speed spindle-hydrostatic bearings, air pressure-bearing, mixed ceramic bearings, magnetic bearing structure of the form. Spindle cooling general use within the water or air cooled.
High-speed processing machine-driven system should be able to provide 40 ~ 60 m / min of the feed rate, with good acceleration characteristics, can provide 0.4 m/s2 to 10 m/s2 acceleration and deceleration. In order to obtain good[FS:PAGE] processing quality, high-speed cutting machines must have a high enough stiffness. Machine bed material used gray iron, can also add a high-damping base of concrete, to prevent cutting tool chatter affect the quality of processing. A high-speed data transfer rate, can automatically increase slowdown. Processing technology to improve the processing and cutting tool life. At present high-speed machine tool manufacturers, usually in the general machine tools on low speed, the feed of the rough and then proceed to heat treatment, the last in the high-speed machine on the half-finished and finished, in improving the accuracy and efficiency at the same time, as far as possible to reduce processing Cost.

2.2 High-speed machining tool

High-speed machining tool is the most active one of the important factors, it has a direct impact on the efficiency of processing, manufacturing costs and product processing and accuracy. Tool in high-speed processing to bear high temperature, high pressure, friction, shock and vibration, such as loading, its hardness and wear-resistance, strength and toughness, heat resistance, technology and economic performance of the basic high-speed processing performance is the key One of the factors. High-speed cutting tool technology development speed, the more applications such as diamond (PCD), cubic boron nitride (CBN), ceramic knives, carbide coating, (C) titanium nitride Carbide TIC (N) And so on. CBN has high hardness, abrasion resistance and the extremely good thermal conductivity, and iron group elements between the great inertia, in 1300 ℃ would not have happened significant role in the chemical, also has a good stability. The experiments show that with CBN cutting tool
HRC35 ~ 67 hardness of hardened steel can achieve very high speed. Ceramics have good wear resistance and thermal chemical stability, its hardness, toughness below the CBN, can be used for processing hardness of HRC <5 0 parts. Carbide Tool good wear resistance, but the hardness than the low-CBN and ceramics. Coating technology used knives, cutting tools can improve hardness and cutting the rate, for cutting HRC40 ~ 50 in hardness between the workpiece. Can be used to heat-resistant alloys, titanium alloys, hightemperature alloy, cast iron, Chungang, aluminum and composite materials of high-speed cutting Cut, the most widely used. Precision machining non-ferrous metals or non-metallic materials, or the choice of polycrystalline diamond Gang-coated tool.

2.3 High-speed processing technology
High-speed cutting technology for high-speed machining is the key. Cutting Methods misconduct, will increase wear tool to less than high-speed processing purposes. Only high-speed machine tool and not a good guide technology, high-speed machining equipment can not fully play its role. In high-speed machining, should be chosen with milling, when the milling cutter involvement with the workpiece chip thickness as the greatest, and then gradually decreased. High-speed[FS:PAGE] machining suitable for shallow depth of cut, cutting depth of not more than 0.2 mm, to avoid the location of deviation tool to ensure that the geometric precision machining parts. Ensure that the workpiece on the cutting constant load, to get good processing quality. Cutting a single high-speed milling path-cutting mode, try not to interrupt the process and cutting tool path, reducing the involvement tool to cut the number to be relatively stable cutting process. Tool to reduce the rapid change to, in other words when the NC machine tools must cease immediately, or Jiangsu, and then implement the next step. As the machine tool acceleration restrictions, easy to cause a waste of time, and exigency stop or radical move would damage the surface accuracy. In the mold of high-speed finishing, in each Cut, cut to the workpiece, the feed should try to change the direction of a curve or arc adapter, avoid a straight line adapter to maintain the smooth process of cutting.

3 Die in high-speed milling processing of
Milling as a highly efficient high-speed cutting of the new method,in

Mould Manufacturing has been widely used. Forging links in the regular production model, with EDM cavity to be 12 ~ 15 h, electrodes produced 2 h. Milling after the switch to high-speed, high-speed milling cutter on the hardness of HRC 6 0 hardened tool steel processing. The forging die processing only 3 h20min, improve work efficiency four to five times the processing surface roughness of Ra0.5 ~ 0.6m, fully in line with quality requirements.

High-speed cutting technology is cutting technology one of the major developments, mainly used in automobile industry and die industry, particularly in the processing complex surface, the workpiece itself or knives rigid requirements of the higher processing areas, is a range of advanced processing technology The integration, high efficiency and high quality for the people respected. It not only involves high-speed processing technology, but also including high-speed processing machine tools, numerical control system, high-speed cutting tools and CAD / CAM technology. Die-processing technology has been developed in the mold of the manufacturing sector in general, and in my application and the application of the standards have yet to be improved, because of its traditional processing with unparalleled advantages, the future will continue to be an inevitable development of processing technology Direction.

高速铣削

高速切削加工是一种先进制造技术，不同于传统加工方式。它的主轴转速高、切削进给速度高、切削量小，单位时间内的材料切除量却增加3～6 倍。它以高效率、高精度和高表面质量为基本特征，在汽车工业、航空航天、模具制造和仪器仪表等行业中获得了广泛的应用，取得了重大的经济效益，是当代先进制造技术的重要应用。长期以来，人们对模具的加工一直采用铣削一磨削或者电火花(EDM)加工、打磨、抛光的方法。虽然电火花可加工硬度很高的工件，但较低的生产率使它的应用受到制。随着高速加工技术的发展，采用高速切削取代磨削抛光和电加工进行模具加工已成为可能。使加工周[FS:PAGE]期大为缩短，加工质量得到可靠保证，加工成本降低。

1 高速切削加工的优势

高速切削加工作为模具制造中集高效、优质、低耗于一身的先进制造技术。在常规切削加工中备受困扰的一系列问题，通过高速切削加工的应用得到了解决。

1.1 提高生产率

高速切削的主轴转速、进给速度与传统切削加工相比，发生了本质性的飞跃，其金属切除率提高了30%~40%，切削力降低了30%，刀具的切削寿命提高了70%。还可加工淬硬零件，许多零件一次装夹可完成粗、半精和精加工等全部工序，对复杂型面也能达到零件表面质量要求，进而提高了加工生产率和产品的市场竞争力。

1.2 改善加工精度和表面质量

高速机床普遍具备高刚性和高精度等特点，加工时切削深度小，而进给速度较快，切削力低，工件热变形减少，而加工精度很高，表面粗糙度很小。高速铣削可获得无铣痕的加工表面，使零件表面质量大大提高。加工铝合金时可达Ra0.40.6um，加工钢件时可达Ra0.2～0.4um。

1.3 减少切削产生的热量

因为铣床主轴高速旋转，切削加工是浅切削，同时进给速度很快，刀刃和工件的接触长度和接触时间非常短，减少了刀刃和工件的热传导。高速切削采用干铣或油一气(油雾)润滑系统，避免了传统加工时在刀具和工件接触处产生大量热的缺点，保证刀具在温度不高的条件下工作，延长了刀具的使用寿命。

1.4 有利于加工薄壁零件

高速切削时的切削力小，有较高的稳定性，可加工高质量同本公司内部员工相比可能是非常优秀的，但是同其他的公司的员工相比工作绩效可能算不了优秀。就我们中国实际来说，我们使用标杆分析法来确定员工培训需求是简单有效的。这种学习标杆对象可以是外部的，也可以是内部和外部的结合。首先要明确企业的发展战略。通过对企业内外部环境和组织资源等分析，明确企业未来发展的目标和业务重点。根据企业的发展战略寻找可以比照的标杆企业，通过比较分析，最后确定标杆企业。在确定标杆企业后，有一项，是了解其发展战略，还是其市场占有率和市场增长率，还是员工各方面的情况等等，这要根据本企业的实际情况来确定。由于企业在不同的发展时期，其着力点是不同的，即企业需要投入的物力人力财力的重点是不同的。所以在一定的时期内，企业要准确地选定其跟标杆企业比较的部门和岗位，这样更加具有实际意义，因为标杆企业并不是处处都好，而且有些方面进行比较没有多少实际意义，再者这样可以更充分地集中利用企业的有限资源。确定标杆企业后，然后拿本企业的相应的部门和员工同标杆企业进行比较，可以发现两者在工作绩效的差距，比较分析，寻找原因，根据本企业的实际，最后确定培训需求。培训是需要成本的，如果没有通过有效的方式，去确定企业是否需要培训以及培训的方式，而是盲目进行培训，这样的培训是难以取得预期的效果。有比较才有区别，这种培训分析模型简单实用。

1.5 可部分替代某些工艺，如电火花加工、磨削加工

高速切削的一大特点，高速切削已可加工硬度达HRC60 的零件。采用带涂层的硬质合金刀具加工模具，直接将淬硬工具钢一次安装加工成形，有效地避免了零件多次安装造成的装夹误差，提高了零件的几何位置精度。在传统加工模具的工艺中，对热处理硬化后的工件需进行电火花加工，用高速切削加工替代传统切削的加工方法，可以省去模具制造工艺中的电火花加工，简化了加工工艺和投资成本。高速铣削加工可在专用的CNC 机床或加工中心上进行，也可在加装高速主轴的普通机床上进行。后者不仅具有普通机床的加工能力，而且还可进行高速铣削，减少了设备投资，增加了机床柔性。高速切削可以使加工效率提高、质量提高、工序简化，机床投资和刀具投资及维护费用上升，但综合比较，可以显著提高经济效益。

2 高速铣削加工

高速铣削加工的主[FS:PAGE]要技术高速切削技术是切削加工技术的发展方向之一，它随着C N C 技术、微电子技术、新材料和新工艺等技术的发展而迈上更高的台阶。高速机床和高速刀具是实现高速切削的前提和基本条件，在高速切削加工中对高速机床的性能和刀具材料的选择有严格的要求。

2.1 高速铣削加工机床为了实现高速切削加工

一般采用高柔性的高速数控机床、加工中心，也有的采用专用的高速铣、钻床。机床同时具有高速主轴系统和高速进给系统，高的主轴刚度特性，高精度定位功能和高精度插补功能，特别是圆弧高精度插补功能。高速切削加工对机床的工艺系统提出了更高的要求，主要表现在以下几个方面：

高速铣削机床必须具有高速主轴，主轴的转速10000~100000m/min，功率大于15kW。还应具有快速升速、在指定位置快速准停的性能。主轴的轴向间隙不大于0 .0 0 0 2 m m 。高速主轴常采用液体静压轴承式、空气静压轴承式、混合陶瓷轴承、磁悬浮轴承式等结构形式。主轴冷却一般采用内部水冷或气冷。

高速加工机床的驱动系统应能够提供40～60m/min 的进给速度，具有良好的加速度特性，能够提供0.4m/s2 到10m/s2的加速度和减速度。为了获得良好的加工质量，高速切削机床必须具有足够高的刚度。机床床身材料采用灰铸铁，还可以在底座中添加高阻尼特性的混凝土，以防止切削时刀具颤振影响加工质量。具有高速数据传输率，能够自动加减速。加工工艺有利于切削加工和提高刀具寿命。目前高速机床的厂家，通常在普通机床上进行低速、大进给的粗加工，然后进行热处理，最后在高速机床上进行半精加工和精加工，在提高精度和效率的同时尽可能地降低加工成本。

2.2 高速切削加工刀具

刀具是高速切削加工中最活跃重要的因素之一，它直接影响着加工效率、制造成本和产品的加工精度。刀具在高速加工过程中要承受高温、高压、摩擦、冲击和振动等载荷，因此其硬度和耐磨性、强度和韧性、耐热性、工艺性能和经济性等基本性能是实现高速加工的关键因素之一。高速切削加工的刀具技术发展速度很快，应用较多的如金刚石(P C D)、立方氮化硼(C B N)）、陶瓷刀具、涂层硬质合金、(碳)氮化钛硬质合金T I C (N)等。立方氮化硼具有很高的硬度、极强的耐磨性和良好的导热性，与铁族元素之间有很大的惰性，在1300℃也不会发生显著的化学作用，还具有良好的稳定性。实验表明，用CBN 刀具切削硬度HRC35～67 的淬火钢可以达到很高速度。陶瓷材料具有良好的耐磨性和热化学稳定性，其硬度、韧性低于C B N ，可用于加工硬度H R C < 5 0 的零件。硬质合金刀具耐磨性好，但硬度比立方氮化硼和陶瓷低。采用刀具涂层技术，可以提高刀具硬度和切削加工的速度，适合切削硬度在HRC40～50 之间的工件。可用于耐热合金、钛合金、高温合金、铸铁、纯钢、铝合金及复合材料的高速切削，应用最为广泛。精密加工有色金属或非金属材料时，选用聚晶金刚石或金刚石涂层刀具。

2.3 高速加工工艺

高速切削的工艺技术也是进行高速切削加工的关键。切削方法选择不当，会使刀具加剧磨损，达不到高速加工的目的。只有高速机床和刀具没有好的工艺技术指导，高速切削加工设备也不能充分发挥作用。在高速切削加工中，应尽量选用顺铣加工，顺铣时刀具切入工件的切屑厚度为最大，随后逐渐减小。高速切削加工适于浅的切深，切削深度不超过0.2mm，可避免刀具的位置偏差，确保加工零件的几何精度。保证工件上的切削载荷恒定，以获得好的加工质量。高速切削采用单一路径顺铣切削模式，尽量不中断切削过程和刀具路径，减少刀具的切入切出次数，以获得相对稳定的切削过程。减少刀具的急速换向，在换向时NC机床必须立即停止或降速，再执行下一步操作。由于机床的加速度限制，易造成时间浪费，而且急停或急动会破坏表面精度。在[FS:PAGE]模具的高速精加工中，在每次切入、切出工件时，进给方向的改变应尽量采用圆弧或曲线转接，避免采用直线转接，以保持切削过程的平稳性。

3 高速铣削在模具加工中的应用

高速铣削作为高效切削加工的新方法，在模具制造中得到了广泛应用。在常规生产连杆锻模时，用电火花加工型腔需12～15h，电极制作2h。改用高速铣削后，采用高速立铣刀对硬度H R C 6 0 的淬硬工具钢进行加工。整个锻模加工只需3h20min，工效提高4～5 倍，加工表面粗糙度达Ra0.5～0.6m ，质量完全符合要求。高速切削技术是切削加工技术的主要发展方向之一，目前主要应用于汽车工业和模具行业，尤其是在加工复杂曲面、工件本身或刀具刚性要求较高的加工领域等，是多种先进加工技术的集成，其高效、高质量为人们所推崇。它不仅涉及到高速加工工艺，而且还包括高速加工机床、数控系统、高速切削刀具及C A D / C A M 技术等。模具高速加工技术目前已在发达国家的模具制造业中普遍应用，而在我国的应用范围及应用水平仍有待提高，由于其具有传统加工无可比拟的优势，仍将是今后加工技术必然的发展方向。

目录

工程英语对话 1(问候和介绍).............................................................................................................................1

工程英语对话2(交谈语言).................................................................................................................................2

工程英语对话3(日期和时间).............................................................................................................................3

工程英语对话4(天气环境).................................................................................................................................4

工程英语对话5(会议磋商).................................................................................................................................5

工程英语对话6(工程项目).................................................................................................................................7

工程英语对话7(进度与计划).............................................................................................................................8

工程英语对话8(技术资料与图纸).....................................................................................................................9

工程英语对话9(公用工程)...............................................................................................................................11

工程英语对话10(施工现场).............................................................................................................................12

工程英语对话11(设备检验).............................................................................................................................14

工程英语对话12(土建工程).............................................................................................................................16

工程英语对话13(施工机械).............................................................................................................................17

工程英语对话14(常用机械).............................................................................................................................18

工程英语对话15-16(工程材料)........................................................................................................................19

工程英语对话17(工艺管道).............................................................................................................................21

工程英语对话18(质量管理).............................................................................................................................23

工程英语对话19(试车与安装调试).................................................................................................................24

工程英语对话20(在宴会上).............................................................................................................................25

工程英语对话1(问候和介绍)

1 Welcome to China.

欢迎你到中国来｡

2 W[FS:PAGE]elcome to our job site.

欢迎你到我们工地来｡

3 I wish we shall have a friendly cooperation in coming days.

希望今后友好合作｡

4 Let us work together for our common job.

让我们为共同的事业一起工作吧!

5 Allow me to introduce myself, my name is yuan...

请允许我介绍自己,我的名字叫袁..｡

6 Please allow me to introduce a fellow of mine, Mr.___.

请允许我给你介绍一位我的同事,某先生｡

7 I am a manager. (project manager, resident construction manager, construction superintendent, controller staff member, engineer, technician, economist, supervisor, foreman, worker)

我是经理｡(项目经理､驻工地总代表､工地主任､管理员､职员､工程师､技术员､经济员､检查员､

工长､工人)｡

8 I work in the Second Construction Company of SINOPEC.(Market Department, Engineering Department).

我在中国石化集团第二建设公司(市场开发部､工程部)工作｡

9 My technical specialty is civil engineering.(chemical engineering, process, mechanical equipment ,electrical, instrumentation, piping, welding, furnace building, corrosion prevention, thermal-insulation, heating-ven-tilation, quality control).

我的技术专业是土建工程｡(化工工程､工艺､机械设备､电气､仪表､管道､焊接､筑炉､防腐､保温､

采暖通风､质量管理)｡

10 What is your speciality?

你的专业是什么?

11 I am a mechanician.(electrician, Pipelayer, welder, carpenter, turner, blacksmith, builder, erector, riveter,rigger, concrete worker, engine-driver,repair worker).

我是一个机械工｡(电工､管工､焊工､木工､车工､铁工､建筑工人､安装工人､铆工､起重工､混凝土工､司机､维修工)｡

12 What is your nationality? Are you American?(English, Japanese, German, French, Italian, Romanian).

你是什么国籍的?你是美国人吗?(英国人､日本人､德国人､法国人､意大利人､罗马尼亚人)｡

13 Can I have your name, please?

请问你的名字?

14 Which department do you belong to?

你在那家公司工作?

15 Kindly give us your advice, please.

请多指教｡

16 Thanks for your direction.

感谢你的指导｡

17 Happy Spring Festival!

春节快乐!

18 Merry Christmas!

圣诞节愉快!

19 Congratulations to your National Day!

祝贺你们的国庆节!

工程英语对话2(交谈语言)

37 Do you speak English?

你能讲英语吗?

38 Let us talk English?

让我们用英语交谈吧!

39 can speak English only a little, do you understand me?

我只能说一点英语,你能听懂吗?

40 Excuse me; sometimes I make mistakes when I speak English.

请原谅,我讲英语有时会说错｡

41 Speak slowly, please. I intend to learn to speak English.

请讲慢一点,我想学着讲一点英语｡

42 I am very sorry. I can not speak English very well, but I can read document in English.

我很抱歉,我的英语说得不好,但我能看懂英文资料｡

43 Please write down the English words of this for us.

请用英文字写出来给我们[FS:PAGE]看｡

44 Write this word in English, please.

请将这字写出英文来｡

45 I can not understand you, say it again, please.

我不懂你讲的,请再说一遍｡

46 Do you know how we should express the idea in English?

你可知道我们应该如何用英文表达这个意思?

47 What does this word mean?

这字是什么意思?

48 We should like to have an interpreter, let us call him.

我们应该找一个翻译来｡

49 Is my pronunciation correct?

我的发音对吗?

50 I have trouble with pronunciation.

我在发音上有困难｡

51 How many languages do you speak?

你能讲几种语言?

52 I can read (speak) English only with the help of a dictionary. ( tape recorder).

我仅能借助字典(磁带录音机)阅读(讲说)英语｡

53 Do you speak Chinese? (Can you write Chinese character?

你能讲汉语吗?你会写汉字吗?

54 Please tell me how to spell the English word.

请告诉我怎样拼读这个英文字｡

55 I do not understand, can you repeat it?

我不懂,你能重复一次吗?

56 I can not catch up with you .

我赶不上你｡

57 I can follow you.

我能听懂你的话｡

58 Let the interpreter continue.

让翻译接着讲｡

59 please put the sentence into Chinese (English).

请把这句子译成汉语(英语)｡

60 Have you a mind to learn Chinese?

你想学汉语吗?

工程英语对话3(日期和时间)

61 What month is this?

现在是几月份?

62 This is January. (February, March, April, May, June, July, August, September, October, November, December).

现在是元月份｡(二月､三月､四月､五月､六月､七月､八月､九月､十月､十一月､十二月)｡

63 What day is today?

今天是星期几?

64 Today is Sunday. (Monday, Tuesday, Wednesday, Thursday, Friday, Saturday).

今天是星期日｡(一､二､三､四､五､六)

65 What is the date today?

今天是几号?

66 Today is April sixth, nineteen eighty-two.

今天是一九八二年四月六日｡

67 What time is it?

现在几点钟?

68 It is six o’clock.

现在是六点钟｡

69 It is seven past nine.

现在是九点过七分｡

70 It is a few minutes after three.

现在是三点过几分｡

71 It is a quarter to ten.

现在是十点差一刻｡

72 Will you be here at eight o ’clock tomorrow?

请你明天八点钟到这里来,行吗?

73 We shall come at half past seven, when will you come?

我们七点半钟来,你什么时间来?

74 We shall be on time, I hope.

我希望我们将按时到达｡

75 We get to work at seven thirty every morning and finish working at eleven thirty before noon. (a.m.)

我们每天早上七点三十分开始工作,到十一点三十分结束工作｡(午前)

76 We work from two until six o ’clock afternoon (p.m.) every day.

我们每天下午从两点到六点工作｡(下午)

77 We have breakfast at seven.

我们七点钟早餐｡

78 We have dinner at eleven forty-five.

我们十一点四十五分进午餐｡

79 We have supper at six afternoon.

我们下午六点进晚餐｡

80 We have a day of rest on Sunday every week.

我们每周星期日休息｡

工程英语对话4(天气环境)

81 It is very fine today; the weather is[FS:PAGE] suitable for our work.

今天天气很好,适合我们工作｡

82 It is not at all a nice day. It will get colder.

天气一点也不好,要变冷起来｡

83 We can not continue the outdoor work, because it is raining (sleeting) now.

因为现在下雨(雨雪),我们不能继续在室外工作｡

84 It is going to snow (hail) tomorrow, some measures must be taken to prevent freezing.

明天将下雪(冰雹),为预防冰冻必须采取一些措施｡

85 The lifting work on site will be compelled to stop, owing to the strong wind. (A dense fog).

由于强风(浓雾),现场起重吊装工作将被迫停止｡

86 We have a nap (interval) after lunch in hot season.

热天午餐后,我们有一个午睡(中休)时间｡

87 The weather is warm (cold) and sunny (cloudy) here.

这里气候温和(寒冷),阳光充沛(阴天多云)｡

88 What is the weather forecast for today?

今天天气预报怎样?

89 The weatherman says: the highest temperature during the day will be twenty one degrees centigrade (21℃).

天气预报员说:今天白天最高气温为摄氏温度二十一度｡

90 The temperature will drop to five above (below) zero tonight.

今晚温度将降到零上(下)五度｡

91 It is spring (summer, autumn, winter) time now.

现场是春天｡(夏､秋、冬)

92 This road leads to the factory. (Post Office, Telegraph Office, Telephone Booth, Travel Agency, Custom House, Bank , Hotel, Restaurant, Department Store, Book Store, Hospital, Theatre , Park).

这条路通到工厂｡(邮局､电报局､电话间､旅行社､海关､银行､酒店､餐厅､百货商店､书店､医院､戏院､公园)｡

93 There is an equipment in front of the building. (Behind the water tower, under the pipe rack, on the floor, inside the steel structure, in the workshop).

在建筑物前面(在水塔后面､在管廊下面､在地面上､在钢结构里面､在车间内)有一台设备｡

94 Our construction site is north (south, east, west) of Nanjing, near the Changjiang River.(Yantze River, yellow River).

我们的工地在南京以北(南､东､西),靠近长江｡(扬子江､黄河)

95 It is about twenty-five kilometers (miles) from here to Lanzhou.

这里离兰州约二十五公里｡(哩)

96 It is only a short way, turn left (right) at the next cross street, and then go straight on.

离这里只有一小段路,到下一个十字路口向左(右)拐,然后一直向前走就到｡

97 It is very convenient from here to Shanghai. (Beijing, Tianjing, Guangzhou , Suzhou).

这里到上海(北京､天津､广州､苏州)很方便｡

98 You can get there by train. (Airplane, ship, bus)

你可以乘火车(飞机､轮船､公共汽车)去｡

99 If it should rain tomorrow, the work would be postponed for some days.

如果明天下雨,工作就要延期几天｡

100 The climate quite agrees with us.

这气候对我们很适宜｡

工程英语对话5(会议磋商)

101 Our meeting will be next Tuesday at eight o ’clock.

我们的会议将在下星期二八点钟举行｡

102 We want to change our meeting from Monday to Wednesday.

我们想把会议由星期一改[FS:PAGE]为星期三｡

103 Sit down, please. Have a smoke and a cup of tea.

请坐,请抽烟､喝茶｡

104 Which problems shall we discuss today?

我们今天讨论哪些问题?

105 Today we shall discuss the question of hydraulic (pneumatic) test.

今天我们将讨论水压､(气压)试验问题｡

106 Please give us your opinion. (Point of view, ideas)

请把你的意见(观点､想法)告诉我们｡

107 We must know your opinion.

我们必须知道你的意见｡

108 We are willing to accept your suggestion. (Plan)

我们乐于采纳你的建议(计划)｡

109 Your suggestion suits us. We agree.

你的建议适合我们,我们同意｡

110 Please forgive me. We have different (opposite) views on this. Our opinion is …

请原谅,我们对此有不同的(相反的)看法｡我们的意见是….

111 I am very sorry, but I disagree with you.

我很报歉,我不同意你说的｡

112 We should be able to settle this question.

我们应该能够解决这个问题｡

113 We would like to hear your opinions.

我们想听一下你的意见｡

114 We must act according to the contract.

我们应该按照合同办事｡

115 Thanks for the advice, but this is something we have to figure out (workout) ourselves.

感谢你的劝告,但此事我们要自己考虑一下｡(解决)

116 I do not see any point in discussing the question any further.

我认为进一步讨论此事没有必要｡

117 Let us discuss these problems one by one. (step by step)

让我们一个一个地(一步一步地)讨论这些问题｡

118 Do you agree with me?

你同意我吗?

I agree.

我同意｡

I disagree.

我不同意｡

I agree with you, but with some reservations.

我同意,但有某些保留｡

119 I think so.

我想是这样｡

I do not think so.

我不这样想｡

120 Shall we have a break?

我们休息一下好吗?

121 It is a question which we shall not discuss here.

这个问题我们将不在此讨论｡

122 We have not get fully determined.

我们尚未完全决定｡

123 This is something beyond our comprehension.

这是我们不可理解的事｡

124 I regret to say that I can not agree with you.

我很报歉(遗憾),不能同意你｡

125 We hold the opinion of our own.

我们坚持我们的意见｡

126 Let us decide on this point.

让我们决定这一点｡

127 We decide to do so.

我们决定这样办｡

128 This problem must be reported to the higher level, they have the final say to make decisions.

这个问题应该呈报上级,由他们作最后决定｡

129 Your side will be held responsible for all the consequences arising there from.

由此产生的一切后果由你方负责｡

130 Let us draft a resolution about it.

让我们为此起草一项决议｡

131 Please sign your name to the minutes of the meeting.

请在会议记录上签字｡

132 We shall meet again tomorrow morning.

我们明天早上接着开会｡

133 Let us put this matter aside for sometimes, Good-bye.

这事过些时候再说,再见!

134 Your cooperation means much to us.

你们的合作对我们是很重要的｡

工程英语对话6(工程项目)

135 A project execution is usually divided into some elementary phases, such as[FS:PAGE]: engineering, procurement and transportation, and field construction.

一个工程项目的实施通常可分为几个基本阶段:工程设计､采购和运输､以及现场施工｡

136 We are building an ethylene plant with an annual capacity of 300,000 metric tons.

我们正在建设一座年产三十万吨的乙烯工厂｡

137 The contract number of this project is CJC78-8.

这个项目的合同号是 CJC78-8｡

138 The Seller (vendor) is Toyo Engineering Corporation (TEC) of Japan.

卖方(卖主)是日本的东洋工程公司｡(简称 TEC)

139 The Buyer (customer, client) is China National Technical Import Corporation. (CNTIC)

买方(主顾､顾客)是中国技术进口总公司｡(简称 CNTIC)

140 China National Chemical Construction Corporation (CNCCC) contracts for domestic and overseas chemical projects.

中国化工建设总公司(简称 CNCCC)承包国内和海外的化工工程｡

141 We can contract to build turn-key plant, undertake single items of projects as a subcontractor or provide labor services.

我们可以承建成套工厂或分包单项工程或提供劳务｡

142 The “UHDE” Corporation of Federal Germany takes part in this project as a patent licenser. (Owner of the know-how)

联邦德国的“伍德”公司作为一个技术专利执证者(专门技术所有者)参加此项工程｡

143 Are you the Seller’s Representative on the job site?

你是卖方的现场代表吗?

144 I am the Buyer’s General Representative. (GR)

我是买方的总代表｡(简称 GR)

145 It is an inquiry (commercial and technical proposal, approval, agreement, protocol, and annex, technical appendix) about this project.

这是这个项目的询价书｡(商务和技术报价书､批准书､协议､会议记录､附加条件､技术附件)

146 There are many information in the technical proposal, which including: process flow, process description, capacity of the plant, performance of the product.

技术报价书中有很多资料,包括:工艺流程､工艺说明､生产能力､产品特性等｡

147 There are two units (installations) in the contract plant. (Within the battery limits)

在合同工厂内(界区范围内)有两个车间｡(装置)

148 The project team normally consists of project engineer, design engineer, schedule engineer, and various specialists.

项目工作组通常包括有项目工程师､设计工程师､计划工程师､以及各类专家｡

149 We can evaluate the results of field construction by four criteria, which are quality, time, cost and safety.

我们可以通过四个指标来评价现场施工的成绩,即质量､时间进度､费用和安全｡

150 I am responsible for the technical (scheduling, inspection, quality control) work of this project. (Area)

我负责这个项目(区域)的技术(技术､检查､质量控制)工作｡

151 Would you tell us the technical characteristic about this project?

你能告诉我们有关这个工程项目的技术特性吗?

152 Please give a description about this project.

请对这个工程项目作一个叙述说明｡

153 The project is certain to be a success.

这个项目一定会得到成功｡

154 Do you have any reference materials [FS:PAGE]about this project?

你有关于这个工程项目有参考资料吗?

工程英语对话7(进度与计划)

155 We should work according to the overall schedule chart (the construction time schedule) of the project.

我们应该按照工程项目的总进度表(建设进度表)工作｡

156 The effective date of this contract will begin from July sixth, nineteen eight-three.

这个合同的有效期将从一九八三年七月六日开始｡

157 The Seller will provide preliminary (final) technical documents for Buyer in May.

卖方将于五月份向买方提供初步(最终)技术文件｡

158 The basic (detailed) process design will be issued before August.

基本的(详细的)工艺设计资料将于八月前发出｡

159 Our major planning items contain estimating of cost and construction schedule.

我们主要的计划工作项目包括费用预算和施工进度｡

160 We shall have a design collecting (preliminary design, final design) meeting next month.

下个月我们将召开设计数据收集(初步设计､最终设计)会议｡

161 On our most projects Critical Path Method (CPM) is used for scheduling.

在我们的大多数工程项目中都采用“统筹法”(即关键路线方法,简称 CPM)安排计划｡

162 Field erection work (civil work) will begin in October this year and complete on June first next year.

现场安装工作(土建工作)将自今年十月开始至明年六月一日完工｡

163 This contract plant will start-up (put in commissioning) on November thirty this year.

这座合同工厂将于今年十一月三十日开车(投产)｡

164 The date of acceptance of this plant will be April sixth, nineteen eighty-four.

这座工厂的交工验收期将在一九八四年四月六日｡

165 The plant is scheduled to be completed around 1985.

工厂计划于一九八五年前后建成｡

166 The Seller ’s operating group (A crew of specialists) will remain on the job until guarantees are met.

卖方操作组(专业工作组)将在现场,一直工作到生产符合保证条件｡

167 We must take the plant through the test run and finally into commercial operation.

我们必须使工厂通过试运转并最终投入工业生产｡

168 Every month we shall establish construction schedule.

每个月我们都要制订建设进度计划｡

169 We shall also make the project schedule report every day.

我们也将每天提出项目进度报告｡

170 We are going to begin this work tomorrow. (Next week, next month).

我们准备明天(下周､下月)开始这项工作｡

171 We must take this work plan into consideration.

我们必须考虑这个工作计划｡

172 We have to change our plan for lack of materials (construction machinery, erection tools)

因缺少材料(施工机械､安装工具),我们只能改变计划｡

173 What is your suggestion about this schedule?

你对这个计划进度有何建议?

174 Give me your opinion on this plan.

请把你对这个计划的意见告诉我｡

工程英语对话8(技术资料与图纸)

175 We completed this task according to the drawing number SD-76.

我们按照图号 SD-76 的图纸完成了这项工作｡

176 According to the technical standard (norm, rules of operation), the erection (alignment, testing) work is now getting on.

安装(校准､试验)工[FS:PAGE]作正在根据技术标准(规范､操作规程)进行｡

177 This is a plot plan (general layout, general arrangement, detail, section, erection, flow sheet, PID, assembly, civil, electrical, control and instrumentation, projection, piping, isometric ) drawing.

这是一张平面布置(总平面､总布置､细部､剖面､安装､流程､带仪表控制点的管道､装配､土建､电

气､自控和仪表､投影､配管､空视)图｡

178 That is a general (front, rear, side, left, right, top, vertical, bottom, elevation, auxiliary, cut-away, birds eye)view.

那是全视(前视､后视､侧视､左视､右视､顶视､俯视､底视､立视､辅助､内部剖视､鸟瞰)图｡

179 How many drawings are there in the set?

这套图纸有几张?

180 Is this a copy for reproduction?

这是一份底图吗?

181 What is the edition of this drawing?

这张图纸是第几版?

182 Is this drawing in effect?

这张图纸有效吗?

183 Is this a revised edition?

这是修订版吗?

184 Will it to be revised yet?

这图还要修订吗?

185 Are there some modifications (revisions) on the drawing?

这张图上有些修改(修正)吗?

186 The information to be placed in each title block of a drawing include: drawing number, drawing size, scale, weight, sheet number and number of sheets, drawing title and signatures of persons preparing, checking and approving the drawing.

每张图纸的图标栏内容包括:图号､图纸尺寸､比例､重量､张号和张数､图标､以及图纸的制图､校对､

批准人的签字｡

187 There are various types of lines on the drawing such as: border lines, visible lines, invisible lines, break lines, phantom lines.

图上有各种形式的线条,诸如:边框线､实线､虚线､剖面线､中心线､引出线､尺寸线､断裂线､假想线｡

188 We have not received this drawing, (instruction book, operation manual) please help us to get it.

我们还未收到这张图纸(说明书､操作手册),请帮助我们取得｡

189 Please send us further information about this item.

请将有关这个项目的进一步的资料送交我们｡

190 I want additional information on this.

我需要这方面的补充资料｡

191 Please explain the meaning of this abbreviation (mark, symbol) on the drawing.

请解释图上这个缩写(标记､符号)的意义｡

192 We comply with and carry out the GB standard (ANSI, BS, AFNOR, JIS, DIN) in this project.

在这个工程中我们遵守并执行中国国家标准 GB｡(美国标准､英国标准､法国标准､日本标准､联邦德国标准)

193 Please make a sketch of this part on the paper.

请将这个零件的草图画在纸上｡

194 Would you lend me your information? (Handbook, brochure)

可否将你的资料(手册､小册)借给我?

195 Please bring us those drawings.

请把那些图纸带给我们｡

196 This is a translated information, it maybe not quite sure.

这是翻译的资料,可能不太确切｡

197 It is a mistake in translation.

那是一个翻译错误[FS:PAGE]5377;

198 The copy is blurred, it is not very clear.

这个复制件被弄模糊了,不太清晰｡

199 Please give us a copy of this information. (Technical specification, instruction, manual, document, diagram, catalog)

请给我们一份这个资料(技术规程､说明书､手册､文件､图表､目录样本)的复印本｡

200 Please send us a technical liaison letter about it.

请给我们一份有关此事的技术联络单｡

201 I received this letter (report, detailed list) last week.

我上周收到此信｡(报告､清单)

202 A working drawing must be clear and complete.

工作图必须简明完整｡

203 Just look at this drawing.

看看这张图吧｡

Please have a look at the drawing.

请看这张图｡

204 Please make a copy of this letter.

请把这信复制一份｡

I have done six copies.

我已复制六份｡

205 Data on equipment can be found in the related information.

有关设备的数据可从有关的资料中找到｡

206 Such information would not avail much.

这些资料用处不大｡

207 Have you any idea how to use the manufacturer’s handbook.

你知道怎样使用这本厂家手册吗?

208 We regard these data as very useful.

我们认为这些数据是很有用的｡

工程英语对话9(公用工程)

209､Public utilities are carefully regulated here.

公用事业在这里受到仔细的管理｡

210､The pressure maintained in the water main is two kilogram per square centimeter.

自来水总管里的水压保持为 2 公斤/平方厘米｡

211､The water has been treated (softened),but it is not drinkable water.

这水经过处理(软化),但不是饮用水｡

212､The common service voltage of electric power in our country is 220/380 volt.

我国普通供电电压为 220/380 伏｡

213､There is a switch board (control panel, distribution box) mounted on the wall.

在墙上装有一个开关板(控制盘､配电箱)｡

214､We have an emergency-standby electric generator with a capacity of 300 kilowatts.

我们有一台三百千瓦的事故备用发电机｡

215､The substation equipped with a transformer of 500 KVA is at the south of the plant.

在工程的南边有一座装有五百千伏安变电器的变电站｡

216､The pressure of the compressed air at the work site is about 7kg/cm2.

工地用压缩空气的气压约为 7 公斤/平方厘米｡

217､There is a steam heating system (air conditioning system ) in the work-shop.

这车间里装有一个蒸汽加热系统(空气调节系统)｡

218､The Post Office is in Renmin Street, it is open from 7.a.m till midnight.

邮局在人民路,从上午 7 点一直开到半夜｡

219､You can send the letter by airmail (regular mail, registered mail).

你可以邮寄航空信(平信､挂号信)｡

220､You may telephone me at ten o’clock, my telephone number is 4907(four    –nine    –0-seven).

你可以在十点中给我打一个电话,我的电话号码是 4907｡

221､Here is the telephone directory.

这是电话号码本｡

222､The telegraphic (cable, telex) address of the guest house[FS:PAGE] is 6080.

招待所的电报(海底电报､用户电报)挂号是 6080｡

223､You may contact the receptionist if you want to make a long distance call (to make overseas call, to send a

overseas telegram).

如果你要打长途电话(海外电话､国际电报),可以与服务员联系｡

224､The cargo vessel (passenger ship) docked at wharf number 5 yesterday afternoon.

货船(客轮)昨天下午停泊在 5 号码头｡

225､There is a freeway (main highway) from here to Nanjing.

从这里到南京有一条高速公路(主要公路)｡

226､There is a limousine service to the Friendship Hotel every day.

每天有开往友谊宾馆的交通车服务｡

227､The quickest way to get there is to take a airplane(taxi, subway, train, bus).

228､You can make your travel arrangement in any branch of the CITS or CAAC.

你可以在中国国际旅行社或中国民航总局的任何分理处办理旅行安排｡

CITS-China International Travel Service          中国国际旅行社

CAAC-General Administration of Civil Aviation of China  中国民用航空总局

工程英语对话10(施工现场)

229､Welcome to our construction site.

230､Glad to have you here.

231､Our job site(施工现场) is over there/here.

232､It is very simple and crude here. Do not mind, please.

这里很简陋,别介意｡

233､Come in, please.  Be quick.  Just a minute, please. Take care.

234､I am a site engineer (director, workshop head, chief of section, foreman, worker, staff member).

工地工程师(厂长､车间主任､班组长､领工､工人､职员)

235､May I introduce our chief engineer to you. (总工程师)

236､Mr.Wang is responsible for this task.. 负责这项工作任务

237､I am in charge of this section.  我负责这个工段｡

238､Here is our engineering office (drawing office, control room, laboratory, meeting room, common room, rest room).

这是我们的工程技术办公室(绘图室､调度室､实验室､会议室､座谈室､休息室)

239､Sit down, please. Let us have a rest.

240､Have some tea (cold drink, ice-sucker 冰棒).

241､I have some thing(question) to ask of you.

242､Would you please tell us something about this?

243､Thanks for your kindness. 感谢费心!

Thanks for your help.

244､The shift will start at half past seven a.m.

早班从 7 点半开始｡

245､We have flexible work hours during the summer.

我们在夏季的工作时间有弹性｡

246､Pay attention to safety!  注意安全｡

247､Put on your safety helmet, please.  请戴上安全帽!

248､Danger! Look out! Get out of the way.  危险!当心!快躲开!

249､Here is our pipe prefabrication workshop (steel structure fabrication shop, machine shop, boiler room, air compressor station, concrete mixing unit).

这里是我们的管道预制车间(钢结构制作厂､机械加工车间､锅炉房､空气压缩机站､混凝土搅拌装置)ʍ[FS:PAGE]77;

250､Let me show you the way. Follow me, please.

251､Would you like to see this process (machine)?

你要看看这工艺方法(机器)吗?

252､Would you like to talk to the welder (inspector)?

你要和焊工(检查员)谈谈吗?

253､The factory (work hop, equipment) produces pipe fittings (spare parts, fasteners).

这工厂(车间､设备)生产管件(配件､紧固件)｡

254､I am sorry, do not touch this, please. 很抱歉､请勿触动!

255､Do not touch that paint, it is wet. 油漆未干,请勿触碰｡

256､Smoking and lighting fires are strictly forbidden at here.

这里严禁烟火｡

257､Look at the sign, danger keep out.

注意标牌,危险勿进｡

258､Out of the bounds for foreigners without special permission.

外国人未经特许不可入内｡

No admittance!

禁止入内!

259､There is a temporary facility for site brickwork.(wood work, ironwork, paintwork)

这是一个现场砖工(木工､铁工､油工)临时设施｡

260､Let me show you around and meet our workers.

让我带你走一圈,并会见我们的工人｡

261､We would like to know your opinion about our site work.

我们想听取你对我们现场工作的意见｡

262､We have just finished the job.

263､We have not finished this work yet.

264､It will be finished under five days.这将在 5 天内完成｡

265､That is a question, I think.   No problem.

266､What is wrong with this?

Something must be wrong with it.  Nothing is wrong.

267､It is difficult to do so. It is easy to do. It is hard to say.

268､It is normal. It is clear.  It is correct. It is all right.

正常清楚正确良好

269､We shall do our best.  尽力做好

270､Some training will fit them for the job.

经过一些训练,他们就能胜任这项工作｡

271､By the end of this month, we shall have carried out our plan.

到这个月底,我们将已实现我们的计划｡

272､All has gone well with our site work plan.

一切均按照我们的现场工作计划进行｡

工程英语对话11(设备检验)

273､Shall we go to the warehouse to check the equipment?

274､I believe that all the machines to be shipped have been pre-assembled (inspected).

我相信所有发运的机器都曾经过预装配(检验)｡

275､Where is the packing list (bill of lading, bill of materials)?

装箱单(提货单､材料清单)在那里?

276､What is the item number (case number) of this equipment?

这台设备的位号(箱号)是多少?

277､How many cases are there in the package of this equipment?

这台设备分几箱包装?

278､What does this mark (symbol) mean?

这个标志(符号)是什么意思?

279､All the equipment must be fitted with nameplates.

所有的设备都钉有铭牌｡

280､First of all, we must check the delivery schedule (date of delivery) of the equipment.

首先,我们必须核查设备的交货计划(交货日期)｡

281､What about the mechanical guarantee of the equipment?

设备的机械保[FS:PAGE]证情况如何?

282､We have placed an order for pumps with a factory.

我们已向一家工厂定购泵机｡

283､We have planned to finish the inspection of the equipment before Sunday.

我们计划在星期天以前完成设备的检查工作｡

284､This equipment is supplied by the Seller (Buyer).

这台设备是卖方(买方)供应的｡

285､This is the equipment in completed conditions, that is the equipment fabricated at plant site.

这是整体设备,那是现场制作的设备｡

286､This equipment is shipped from the Japan (United States of America, England, France, Italy, Federal Republic of Germany, Singapore).

这台设备是从日本(美国､英国､法国､意大利､联邦德国､新加坡)发运过来的｡

287､The equipment is delivered to here by sea (air railway, road).

这台设备是通过海运(空运､铁路､公路)发货到此的｡

288､The port of destination is Hsingkang (Shanghai, Whampoa, Kwangchow, Tsingtao).

到达港是新港(上海､黄埔､广州､青岛)｡

289､The over-sized equipment which is over 3.4 m in width, 3.1m in height, 18m in length and 50 tons in weight.

超限设备的限度为超过宽 3.4 米､高 3.1 米､长 18 米和重量 50 吨｡

290､Please pay attention to the following marks on the package.:

请注意包装箱上的下列标志:

Use rollers     使用滚杠移    Heave here

Handle with care                        小心装卸   Top       上部

Bottom          底部        Inflammable

Fragile            易碎          Do not cast 从此提起

易燃

勿掷 Keep upright 勿倒置   Keep in a cold (dry) place         存于冷(干)处

To be protected from cold (heat)  怕冷(热)

291､How much does this equipment weigh?

这台设备多重?

292､The gross (net)weight of this case is fourteen tons (pounds).

这箱毛(净)重 14 吨(磅)｡

293､Let us check the quantity of the parts (accessories) according to the packing list (shipping list).

让我们根据装箱单(发货清单)来核查零件(附件)数量｡

294､Shall we check it again (once more)?

我们再检查一次(再查一遍)好吗?

295､It has been damaged (rusted) here, let us take a picture (photograph). 此处已经损坏(锈蚀),我们来照个相｡

296､The packaging has to be improved.

这个包装必须改进｡

297､We should record what the damage and lack of parts.

我们应该把损坏和缺件情况作个记录｡

298､We must avoid so far as possible the damage of equipment during storage.

我们必须尽量避免设备在储存期间损坏｡

299､Please sign your name to the check list.

请你在检验[FS:PAGE]单上签个字｡

300､Your side must compensate us for our loss.

你方必须赔偿我们的损失｡

301､We must pack the spare parts into another box..

我们应该将备件另行装箱｡

302､All of the equipment are made in China.(Japan)

所有的设备都是中国(日本)制造的｡

工程英语对话12(土建工程)

303､All of the civil work on the field will be executed by us (our company).

所有现场的土建工作都将由我们(我公司)承担实施｡

304､Civil engineering design is performed on our own at home.

土建工程是根据卖方提供的技术条件设计的｡

306､This is a working (plot plan, vertical layout, structure plan, floor plan, general plan) drawing.

这是施工(平面布置､竖向布置､结构､屋间平面､总)图｡

307､The quality of civil engineering conforms with our domestic technical standard (China National Building Code).

土建工程的质量符合我们国内的技术标准(中国建筑法规)｡

308､Our civil work include construction of roads, buildings, foundations and reinforced concrete structure.

我们的土建工作包括建造道路､建筑物､基础和钢筋混凝土结构｡

309､It will take two weeks to complete this building (foundation).

这房子(基础)需要两周时间才能完成｡

310､Sand, brick, and stone are generally used in constructing houses.

砂､砖和石头通常用于建造房屋｡

311､These are the anchor bolts (rivets, unfinished bolts, high-strength structural bolts) for the structure.

这是用于结构的锚定螺栓(铆钉､粗制螺栓､高强度结构用螺栓)｡

312､The holes of anchor bolts will be grouted with normal (Portland ,non-shrinkage) cement mortar.

这些地脚螺孔将灌入普通(波特兰,无收缩)水泥砂浆｡

313､We usually measure the strength of concrete at 28 days after which has been cast.

我们通常在混凝土灌注后 28 天测定其强度｡

314､The average compressive strength of samples is 500kg/cm2.

试样的平均抗压强度为 500 公斤/平方厘米

315､Our concrete material is mixed in a rotating-drum batch mixer at the job site.

我们用的混凝土是在现场的间歇式转筒搅拌机中搅拌的｡

316､Quality of concrete depends on proper placing, finishing, and curing.

混凝土的质量取决于适当的灌注､抹光和养护｡

317､The workers tend to start the final finishing now.

工人们现在打算开始最后的抹光作业｡

318､The concrete can be made stronger by pre-stressing in our factory.

在我们厂里可以使混凝土通过预加应力得到增强｡

319､Most of construction material can be tested in our laboratory.

我们的实验室可以检验大部分建筑材料｡

320､We shall finish the civil work by the end of the year.

在年底前我们将完成土建工作｡

工程英语对话13(施工机械)

321､We have all kinds of construction machinery on the job site.

我们有各种施工机械在现场｡

322､The truck crane (gantry crane, tower crane, mobile slewing crane, bridge crane, crawler crane) can lift a wei[FS:PAGE]ght of 15 tons.

这台汽车起重机(龙门吊､塔式吊､悬臂汽车吊､桥式吊､履带式起重机)能吊起 15 吨的重物｡

323､The hoisting capacity of that gin pole (girder pole, guy derrick) is sixty tons.

那个起重抱杆(格状抱杆､转盘抱杆)的起重能力为 60 吨｡

324､The brand of this truck is  “JIEFANG” (YUEJIN, HUANGHE ,HINO, NISSAN, TOYOTA, ISUZU, TADANO, KATO, MITSUBISHI, HITACHI, IFA, BENA, SKODA, TATRA, CSEPEL, FIAT FORD, DODGE, GMC, BERALIN, ROMAN, ГИС,ГИП).

这台载重汽车的牌号是“解放”(跃进､黄河､日野､日产､丰田､五十铃､多田野､加藤､三菱､日立､

依发､奔驰､斯柯达､太脱拉､却贝尔､菲亚特､福特､道奇､通用､贝埃标､罗曼､吉斯､吉尔)｡

325､This is a motor hoist (winch) with low (high) wrapping speed.

这是低(高)速电动卷扬机(绞盘)｡

326､What is the horsepower (H.P) of this engine (tractor, excavator, bulldozer, motor scraper, roller)?

这台发动机(拖拉机､挖掘机､推土机､自行铲运机､压路机)的马力是多少?

327､We used to weld pipes with direct current (D.C) are welder (alternating current A.C. welder).

我们总是用直流(交流)电弧焊机焊接管子｡

328､The concrete mixer (concrete truck mixer, concrete vibrator, concrete batch plant) made by Hua-Dong Works are steady in quality and reliable in performance.

华东工厂生产的混凝土搅拌机(搅拌车､混凝土振动器､混凝土搅拌站)质量稳定､性能可靠｡

329､Loaders, fork lifts and air compressors are heavy construction machinery.

装载机､叉车和空气压缩机都是重型施工机械｡

330､We must study the instruction before operation the pipe bender (hand pump, hydraulic testing pump).

在操作弯管机(手压泵､液压试压泵)之前,我们必须先学习说明书｡

331､The thickness of the steel plate handled by this roller mill (shear machine) is 25 millimeters.

这台滚压机(剪切机)加工的钢板厚度可达 25 毫米｡

]332､This lathe (milling, boring, grinding, drilling, gear cutting, planer) machine is of home manufacture.

这台车床(铣床､镗床､磨床､钻床､切齿机､刨床)是我们国内制造的｡

333､All machinery must be lubricated periodically according to the lubrication chart.

所有的机械都必须根据润滑图表定期加油｡

334､To maintain its efficiency, the machinery needs a regular service (check-over, repairing, overhaul).

这台机械需要进行一次定期保养(全面检查､修理､大修),以维持其工作效率｡

335､This machinery is made in China (Great Britain, USA, Canada, Italy, Holland, Japan, Korea, Federal Germany, Democratic Germany, France, Romania, Bulgaria, Poland, Czechoslovakia, Yugoslavia, Hungary, Soviet Union, Swiss, Sweden).

这台机械是中国(英国､美国､加拿大､意大利､荷兰､日本､朝鲜､联邦德国､民[FS:PAGE]主德国､法国､罗马

尼亚､保加利亚､波兰､捷克斯洛伐克､南斯拉夫､匈牙利､苏联､瑞士､瑞典)制造的｡

336､Tell me about the operation of the machine.

请告诉我如何操作这台机器｡

337､Bearings must be lubricated periodically.

轴承必须定期润滑｡

338､Need we make any adjustment of this machine?

我们有必要调整这台机器吗?

工程英语对话14(常用机械)

339､There are many tools in my tool storage unit (tool chest, tool box).

我的工具柜(工具盒､工具箱)里面有很多工具｡

340､Get me a hammer (hacksaw, file, scraper, chisel, socket, wrench, hook spanner, adjustable wrench, pipe

wrench, ratchet wrench, open end wrench, screw driver, hand vice, pliers, pocket knife).

给我拿一把手锤(钢锯､锉刀､刮刀､凿子､套筒扳手､钩扳手､活动扳手､管扳手､棘轮扳手､开口扳

手､螺丝刀､手钳､扁嘴钳､小刀)｡

341､Straightedge rule (square rule, slide gauge, inside and outside micrometer, steel tape, feeler, dial gauge, depth micrometer, wire gage, radius gage, thread pitch gage) is a kind of common measuring tool.

直尺(角尺､游标卡尺､内径和外径千分尺､钢卷尺､塞尺､千分表､深度千分尺､线规､半径规､螺距

规)是一种常用量具｡

342､The precision of this fitter level (cross-test level) is 0.02mm/M.

这个钳工水平仪(框架式水平仪)的精度为 0.02 毫米/米｡

343､We have got the instrument (pressure gauge, thermometer, tachometer, current meter, universal meter) ready for the experiment (test).

我们已经准备好做实验(试验)的仪器(压力表､温度计､转速计､电流表､万用表)｡

344､That is an air (electric) powered grinder (portable grinder, angle grinder, straight grinder, drill, impact wrench, riveting hammer, hammer drill).

那是一个气(电)动砂轮机(手持砂轮机､角型砂轮､直型砂轮､钻机､冲击扳手､铆钉锤､锤钻机)｡

345､Our electrical tools are double insulated and approved to international safety standards.

我们的电动工具都是双重绝缘的,并符合国际安全标准｡

346､Hydraulic pump is the power unit of the hydraulic puller (hydraulic press, hydraulic pipe bender, hydraulic jack).

油压泵是油压拉出器(油压机､油压弯管机､油压千斤顶)的动力装置｡

347､A welder’s kit contains electrode holder, welding torch, helmet shield, portable electrode heating box and temperature measuring pen.

一名焊工的成套工具包括焊钳､焊炬､面罩､手提式焊条加热箱和测温笔｡

348､The diameter of this wire rope (hemp rope, sling) is three-fourth inches (3/4”).

这钢丝绳(麻绳､吊索)的直径为 3/4 英寸｡

349､The lifting capacity of this chain hoist (hydraulic jack, screw jack) is 5tons.

这个吊链(油压千斤顶､螺旋千斤顶)的起重能力为 5 吨｡

350､The[FS:PAGE] vise (parallel-jaw vice) is available to all of the bench work.

所有的钳工工作都可使用台钳(平口钳)｡

351､Grease gun and oiler are the lubrication service tools for machinery.

油枪和注油器都是机械润滑维护工具｡

352､Torque wrenches offer the precision measurement needed to tighten fasteners.

力矩扳手可以提供禁锢螺栓所需的精确力矩计量｡

353､The measuring unit of torque wrench is pound-inch or kilogram-centimeter.

力矩扳手的计量单位为镑-寸或者公斤-厘米｡

354､Is the machine accompanied with some tools (spare parts, accessories)?

这台机器随机带有一些工具(备件､附件)吗?

355､Shall we use a special tool for this job?

我们干这活要使用专用工具吗?

356､Could you tell us how to use (operate, repair, maintain, clean, adjust) this new tool?

你能告诉我们如何使用(操作､修理､维护､清理､调整)这个新工具吗?

357､The tool gets out of order, we must remedy its trouble.

这工具有毛病,我们必须排除它的故障｡

358､The tool is out of repair, it needs an overhaul.

这工具失修,需要拆修｡

359､From your explanation I shall easily handle it.

听了你的说明,我将易于操纵它｡

360､The tools must be well kept.

工具必须妥善保管｡

程英语对话15-16(工程材料)

361 here are some material warehouses(store yards)on the construction site.

在工地上有一些材料仓库(堆场)｡

362 Our store officer is responsible for the warehousing and issuing of materials.

我们的仓库管理员负责保管和发放材料｡

363 We use Scientific-management system for material shortage and its control.

我们应用科学管理体系处理材料短缺及其调节｡

364 These materials are imported from abroad(supplied by the Seller).

这些材料是从国外进口的(卖方供应的)｡

365 What is the feature about it?

这些材料的特性是什么?

366 The construction material answers our purpose satisfactorily.

这种建筑材料能满足我们的需要｡

367 The average traffic fuel (gasoline) consumption of this lorry is 0.3 liter per kilometer (l/km).

这台货车的平均行车柴油(汽油)耗量为每公里 0.3 公升｡

368 Hydraulic oil (lubrication oil )which having a viscosity of about 4.5   °Eat 50℃ can be used for this vehicle (machine).

具有恩氏粘度 4.5°E( 50℃)的液压油(润滑油)可用于此车辆(机器)｡

369 This special oil comes from the “SHELL” company (CALTEX, MOCBIL,GULF, ESSO, CASTROL, BP).

这种特种油来自“壳牌”公司(加德士､飞马､海湾､埃索､卡斯特罗､英国石油公司)｡

370 Cement steel and timber are the most important construction materials used in civil engineering.

水泥､钢材和木材是土建工程中最重要的建筑材料｡

371 Typical structural steel shapes include beams, channels, angles and tees.

典型的结构型钢包括工字钢､槽钢､角钢和丁字钢｡

372 There are four broad classifications of steel : carbon steels, alloy steels, high-strength low-alloy steels and stainless steels.

钢材大致辞可分为四类,即[FS:PAGE]:碳素钢､合金钢､高强度低合金钢和不锈钢｡

373 Copper, zinc, lead, aluminium, bronze and brass are nonferrous metals or alloys.

铜､锌､铅､铝､青铜和黄铜都是有色金属或合金｡

374 This alloy is mainly composed of element chromium and nickel ( titanium, vanadium, manganese).

这种合金主要由元素铬和镍(钛､钡､锰)组成｡

375 The standards “GB” and “YB” provide the method of testing for materials in our country just like the standard ASTM in America.

在我们 GB(国标)和 YB(冶标)规定材料的试验方法,正如美国的 ASTM 标准一样｡

376 We have asbestos (rubber, plastic, glass, paint) products of all kinds.

我们有各种石棉(橡胶､塑料､玻璃､油漆)制品｡

377 Bolt (screw, nut, stud, spring washer, pin, ball bearing, roller bearing) is the most commonly used machine part.

螺栓(螺钉､螺帽､双头螺栓､弹簧垫圈､销､滚珠轴承､滚柱轴承)是最常用的机械零件｡

378 Cast iron cannot compare with steel in tensile strength.

铸铁在抗拉强度上比不上钢｡

379 Erection of the equipment will be carried out according to the specifications and drawings.

设备安装将按照说明书和图纸进行｡

380 All site erection works will be performed by the Buyer under the technical instruction of the Seller.

所有的现场安装工作都应在卖方的技术指导下由买方完成｡

381 The construction company is fully in charge of the administration of all erection work.

建设公司完全负责全部安装工程的行政管理｡

382 Our company cover all construction activities, that is : piling , civil engineering, mechanical erection, piping, electrical, instrumentation, painting and insulation work.

我们公司涉及所有施工活动,包括:打桩､土建工程､机械安装､配管､电气､仪表､油漆和保温绝缘工作｡

383 What is the feature of this cracker (cracking furnace, heating furnace, reactor, mixer, centrifuger,

belt-conveyer) ?

这台裂解器(裂解炉､加热炉､反应器､搅拌器､离心机､皮带输送机)的特点是什么?

384 The spherical tank (gas holder , container) will be shipped in the condition of edge prepared and bent plates.

球罐(气柜､容器)将以板加工和弯板的条件发货｡

385 I think that the on-site training will be necessary for the tank.

我想槽罐焊接工作的现场培训是必要的｡

386 The cooler (condenser, separator, boiler, generator, scrubber, stripper, heat exchanger )is a pressure vessel. It is subject to the pressure vessel code.

这台冷却器是一个压力容器,它必须服从压力容器法规｡(冷凝器､分离器､锅炉､发生器､洗涤器､汽提器､热交换器)

387 The pressure vessel must be inspected by our authoritative organization-Administration of Labour.

压力容器必须接受我们的权威机构劳动总局的监察｡

388 The new reciprocating (centrifugal, opposed-balanced) compressor will be installed next week.\

下周将安装这台新的往复式(离心式､对置平衡式)压缩机｡

389 The distilling column( absorber, column evaporator, regenerator, column washer) is a kind of equipment for outdoor installation.

蒸馏塔(吸收塔､蒸发柱､再生塔､洗涤塔)是一种室外安装的设备｡

390 The TG70 steam turbine has a operation speed of 9600 rotations per minute( RPM).

TG70 型蒸汽透平的运转速度为每分钟 9600 转｡

391 What do you think of this erection work?

你看这项安装工作如何?

392 This low (middle, high ) pressure blower (pump) will be assembled in the No.3 workshop.

这台低(中､高)压鼓风机(泵)将在三号车间里予以装配｡

393 We are adjusting (installing, checking, aligning , leveling, purging )the equipment.

我们正在调整(安装､检查､找正､找平､清洗)这台设备｡

394 The working team will finish the job next week.

工作班组将在下周干完这活｡

395 We can adjust the levelness of the machine by means of shim and screw jack.

我们可以利用垫铁和螺丝千斤顶来调整机器的水平度｡

396 After seven days , the grouted mortar will have concreted, then we shall tighten the anchor bolts.

灌浆在七天以后凝固,我们就将拧紧地脚螺栓｡

397 The alignment of the coupling should be performed by two dial gauges.

靠背轮的找正对准应用两只千分表来进行｡

398 The maximum allowable misalignment of the coupling is 0.02mm.

靠背轮找正的最大允许偏差为 0.02 毫米｡

399 How many radial (axial ) clearnance are there in this bush (journal bearing , thrust bearing) ?

这个轴套(轴颈轴承､止推轴承)的径向(轴向)间隙是多少?

400 Does the bolt fit the nut?

螺栓与螺母不配｡

401 We prefer welding to riveting.

我们认为焊接比铆接好｡

402 Do you know how to assemble (adjust )this new machine?

你知道如何装配(调整)这台新机器吗?

工程英语对话17(工艺管道)

403 The design of the process piping is performed directly on a model of the project.

工艺配管的设计是直接按照工程项目的一个模型完成的｡

404 The model is an actual working tool for piping.

模型是配管用的实际工具｡

405 Piping erection work include: prefabrication, placing, aligning, welding and bolting.

管道安装工作包括:预制加工､安置､对准､焊接和连接｡

406 Our piping prefabrication workshop covers a total area of 1000m2.

我们的管道预制加工厂拥有一千平方米的面积｡

407 We can perform the pipe by following operations: cutting and mechanical chamfering, manual and automatic welding.

我们可以对管子进行下列预制加工:切割和机械加工坡口,手工和自动焊接等｡

408 The computer generates isometric drawings and prints out bill of materials.

计算机绘出管道空视图,并打印出材料明细表｡

409 We shall complete the manhour requirements for the site fabrication (site erection ) of this drawing.

我们将制订这张图纸现场制作(现场安装)所需的工时条件｡

410 Seamless steel tube is made in sizes for 1/8 to 24 inches.

无缝钢管制作的尺寸从八分之一寸到二十四寸｡

411 Spiral-welded steel pipe is available in sizes from 6 to 36 inches.

螺旋焊接钢管的尺寸从六寸到三十[FS:PAGE]六寸｡

412 Two types of end are standard on steel pipes and fittings, that is flanged and screwed.

钢管和管件有两种标准端部型式,即:法兰和丝扣｡

413 This pipe is made of carbon steel (stainless steel ,cast iron, plastic).

这管子是碳素钢(不锈钢､铸铁､塑料)制成的｡

414 We usually use elbow (bend, flange, tee, reducer ) as a kind of pipe fitting.

我们常用弯头(弯管､法兰､三通､大小关)作为一种管件｡

415 What is the installation elevation of this pipeline?

这条管线的安装标高是多少?

416 This pipeline will be installed on the No.8 pipe rack .

这条管线将安装于八号管廊架上｡

417 The transfer medium in this pipeline is liquid ammonia (process air , soft water, alkali liquor, acidic gas).

这条管线的输送介质为液氨(工艺空气､软水､碱液､酸性气体)｡

418 This is a gate valve (check valve, butterfly valve, cut-off valve, magnetic valve, remote valve, relief valve, throttle valve, cock).

这是一个闸阀(止回阀､蝶阀､切断阀､电磁阀､遥控阀､安全阀､节流阀､旋塞)｡

419 Please explain the method of field test and flushing (blowing off )of the pipelines.

请说明管线的现场试验和冲洗(吹净)方法｡

420 We shall conduct the clean water for the hydrostatic test of the austenitic stainless steel pipe.

我们将为奥氏体不锈钢管的水压试验引进净水｡

421 We need a piping material list (list of piping support, bill of welding rod ).

我们需要一份配管材料表(管架一览表､焊条明细表)｡

422 The welding (heat treatment )of pipes have been carried out with incorporated programming.

管子的焊接(热处理)现已按照编写的程序完成｡

423 We can carry out various treatment for the inner surface of pipes, such as sanding , chemical pickling, purging and passivation.

我们可以进行管子内壁的各种处理,诸如:喷砂､化学酸洗､冲洗和钝化｡

424 The outer surface of this pipeline will be painted in green (red, yellow, blue, white, black ,grey, brown ) colour.

这条管线的外表面将涂刷绿(红､黄､蓝､白､黑､灰､棕)色｡

工程英语对话18(质量管理)

425 Total Quality Control(TQC) is a better quality control system.

全面质量管理(简称 TQC)是一种较好的质量管理体系｡

426 TQC over the project will be strengthened.

对于这个工程的全面质量管理将要加强｡

427 To maintain the best quality of the construction work is the important responsibility of the field controllers.

保持施工工作的优良质量是现场管理人员的重要职责｡

428 We possess skilled technician and complete measuring and test instruments used to ensure the quality of

engineering .

我们拥有熟练的技术力量和齐全的检测手段,可以确保工程质量｡

429 Field inspection work is handled (executed, directed )by our Inspection Section.

现场检查工作由我们的检查科管理(实施､指导)｡

430 Our site quality inspector will report to the Project Manager everyday.

我们的现场质量检查员将每天向工程项目经理汇报A[FS:PAGE]377;

431 I want to see the certificate of quality (certificate of manufacturer, certificate of inspection, certificate of

shipment, material certificate, certificate of proof).

我要看看质量证书(制造厂证书､检查证明书､出口许可证书､材料合格证､检验证书)｡

432 Here is the report of chemical composition inspection.

这是化学成份检验报告｡

433 Is it OK(good, guaranteed, satisfied, passed)?

那是正确的(好的､保证的､满意的､合格的)吗?

434 We shall take the sample to test its physical properties (mechanical properties, tensile strength, yield point, percentage elongation, reduction of area, impact value, Brinell hardness).

我们将取样试验其物理性能(机械性能､抗张强度､屈服点､延伸率､断面收缩率､冲击值､布氏硬度)｡

435 We have received Certificate of Authorization for the fabrication and erection of pressure vessels.

我们具有压力容器制作和安装的授权认可证书｡

436 The welds passed the examination of radiographic test (ultrasonic inspection, magnetic testing).

这焊缝通过射线透视检查(超声波探伤､磁力探伤)合格｡

437 Are you a qualified nondestructive testing(NDT) person?

你是具有资格的无损检测人员吗?

438 Let us go to the laboratory to check the radiographic films.

请到试验室去检查透视片子｡

439 This job will have to be done over again.

这活必须返工重做｡

440 The defect must be repaired at once.

缺陷必须立即修理｡

441 This problem of quality needs a further discussion.

这个质量总是需要进一步研讨｡

442 The ISO standards have been used by our company in this project.

国际标准(ISO)已为我公司采用于此工程中｡

443 The testing results fulfill quality requirement.

试验结果达到质量要求｡

444 Check list (quality specification ) has been signed by the controller( inspector, checker).

检验单(质量说明书)已由管理员(检查员､审核人)签字｡

工程英语对话19(试车与安装调试)

445 We shall put the machine to trial (test run) after the erection work has been finished.

这台机器安装工作完成以后就将进行试车｡(试运转)

446 The mechanical completion check list of the unit has been approved by both of the Buyer

representative.

这个装置的机械竣工检验表已由买方和卖方的代表审定｡

447 We should start the installation according to the instruction and operation manual.

我们应该根据说明书和操作手册来开动这个装置｡

’s and Seler ’s

448 The systematic hydrostatic test (dry run , hot test, dynamic test, actual start-up ) is scheduled for next Monday.

系统水压试验(学习､加热试验､动力试验､实际开车)定于下星期一进行｡

449 We have planned to finish the adjustment of the machine before Tuesday.

我们计划在星期二以前完成机器的调试工作｡

450 Before initial start-up of the installation, we must check the equipment carefully.

在装置初次开动以前,我们必须仔细地检查这些设备｡

451 Shall we begin the test run at once?

我们立即开始试车好吗?

452 The compre[FS:PAGE]ssor is loaded up with the medium of air (nitrogen, process gas).\

压缩机以空气(氮气､工艺气体)加载运转｡

453 The turbine had been running for 4 hours before carrying a full load.

透平在满载前已经运转了四个小时｡

454 We shall soon put the chemical installation into commissioning test run. (performance test)

我们将很快地把这个化工装置进行投料试生产｡(性能考核)

455 According to the schedule, the first batch process will be produced on October first this year.

根据进度表,今年十月一日将首次批量生产｡

456 The machine is in good working order.

这台机器运转良好｡

457 The machine is out of order, will you see to it , please.

这台机器运转不好,请你去检看一下｡

458 I felt the machine shake seriously.

我感到这机器震动严重｡

459 The machine parts went hot.

这机器零件发热｡

460 The noise of the machine is very loud.

这台机器噪音很大｡

461 The machine is knocking badly.

这台机器敲击声厉害｡

462 If there arises any abnormal temperature (unusual noises, vibration) , it is necessary to stop the machine and

investigate the cause.

如果产生不正常的温升(异常噪音､振动),必须停车查明原因｡

463 You must turn off the switch when anything goes wrong with the motor.

如果电动机有什么毛病时,你必须关掉开关｡

464 We have planned to finish the adjustment of the machine before Tuesday.

我们应该渐渐地增加压缩机的压力,并逐步投入满负荷运行｡

465 The rotation number of the machine is on the increase.

机器的转数在增加｡

466 After a few hours running , we shall check the machine; and replace the oil , if necessary.

在数小时运转后,我们将检查机器;并在必要时换油｡

467 We shall select the suitable grease in accordance with the lubrication chart.

我们要根据润滑表来选用合适的油脂｡

468 What is the trouble with the machine?

这机器有什么故障?

469 I think the trouble lies here.

我想故障在这里｡

470 It is necessary that we should repair it at once.

我们必须立即修理它｡

471 We shall give the machine another trial at 10 o’clock.

我们将在十点钟把这台机器再试一次｡

472 The machine runs perfectly well , it had been operating with a continuous run of 72 hours.

这强机器运转很好,它至今已连续运转了七十二小时｡

473 The result of the test run satisfied us.

试车结果使我们很满意｡

474 It is not doubtful that the test run will be successful.

试车将会成功是无疑的｡

工程英语对话20(在宴会上)

你好吗?

I am very glad to meet you .

见到你很高兴｡

476 Take this seat, please.

请坐这个座位｡

Sit down, please.

请坐｡

477 Allow me to introduce myself. I am yuan Qifeng.

请让我自我介绍一下,我是,,,｡

May I introduce Mr. Yu.

请让我把于先生介绍给你｡

This is Mr. Li (Mrs.wu, Miss Liu, Comrade Yang).

这位是李先生(吴夫人､刘小姐､杨同志)｡

May I ask your name?

请问你叫什么名字?

478 Welcome to China (Shanghai, Nanjing, Anhui).

欢迎你来中国(上海､南京､安徽)｡[FS:PAGE];

Welcome to our construction site( factory).

欢迎你到我们工地(工厂)来｡

479 Did you have a nice trip?

旅途顺利吗?

Is this your first trip to China?

这是你第一次来中国吗?

480 I hope you will have a pleasant work here.

希望你在这里工作愉快｡

Hope you will enjoy your stay here.

希望你在这里过得愉快｡

481 Please don’t stand on ceremony , if you please.

别客气,请随便｡

Make yourself at home.

请别拘束｡

482 Try some of this Roast Duck.

尝尝这个烤鸭｡

483 Help yourself to that fish.

请吃那个鱼｡

484 Do you want some desert?

你要点甜食吗?

485 Would you like a bowl of soup?

你要一碗汤吗?

486 What would you like to drink?

你想喝点什么?

487 Have a glass of beer (red wine, liquor), please.

请喝一杯啤酒(红酒､白酒)｡

Please try this “Mao Tai” Fenjiu, Gujing, Tequ, Qingdao Beer), it is the best drink in our country (province, city).

请尝喝这茅台洒(汾酒､古井酒､特曲酒､青岛啤酒),这是我国(省､市)最好的酒｡

488 This is a course of Chinese dish, help yourself.

这是一道中国菜,请吃｡

Do you prefer Chinese or Western food?

你喜欢中餐还是西餐?

Shall we have some rice( bread)?

吃点米饭(面包)吗?

489 I don’t know what name of this dish, let us take a look at the menu.

我不知道这菜的名称,让我们来看一下菜谱｡

It is called “Jiaozi” in Chinese, it means meat dumpling.

这仪器中文名叫“饺子”,意思是肉馅面食｡

490 Here is the Western tableware: knife, fork and spoon.

这是西餐用具:刀､叉和匙｡

This is a pair of Chinese chopsticks, try it and see if you like it.

这是一双中国筷子,试试看你是不是喜欢它｡

491 I am very glad you like it , do have more.

我很高兴你喜欢这菜,请多吃些｡

No, thanks, I have had enough.

谢谢,不要了,我够了｡

492 Here’s to the health of our friends-to your health!

为朋友们的健康干杯!

493 May the friendship between us continue to grow-to our friendship and cooperation!

为我们之间的友谊进一步增长——为友谊和合作干杯!

494 Here’s to you (everyone)!

向你(大家)祝酒!

Congratulations!

表示祝贺!

Good luck!

祝你好运!

Cheers!

祝你愉快!

Bottoms up!

干杯!

495 Would you like a cup of tea (milk, coffee, cocoa, orange juice, mineral water)?

你要一杯茶(牛奶､咖啡､可可､桔子汁､矿泉水)吗?

Which do you prefer, coffee or tea?

你喜欢什么,咖啡还是茶?

496 Try our filter cigarettes “ZHONGHUA”(SHANGHAI, DAQIANMEN) , please.

请尝吸我们的过滤咀香烟“中华牌”  (上海牌､大前门牌)｡

497 We give a warm send-off to you!

我们热烈欢送你!

498 Thank you for your work in promoting the modernization of our country.

感谢你为促进我国的现代化而做的工作｡

499 I wish you a pleasant journey!

祝你旅途愉快!

Bon voyage!

一路顺风!

500 Good-by!

再见!

Good night!

晚安｡

Hope to see you again.

希望能再见到你｡

Several factors provided the stimulus for the development of modern control theory:

a. The necessary of dealing with more realistic models of system.

b. The shift in emphasis towards optimal control and optimal system design.

c. The continuing developments in digital computer technology.

d. The shortcoming of previous approaches.

e. Recognition of the applicability of well-known methods in other fields of knowledge.

The transition from simple approximate models, which are easy to work with, to more realistic models, produces two effects. First, a large number of variables must be included in the models. Second, a more realistic model is more likely to contain nonlinearities and time-varying parameters. Previously ignored aspects of the system, such as interactions with feedback through the environment, are more likely to be included.

With an advancing technological society, there is a trend towards more ambitious goals. This also means dealing with complex system with a large number of interacting components. The need for greater accuracy and efficiency has changer the emphasis on control system performance. The classical specifications in terms of percent overshoot, setting time, bandwidth, etc. have in many cases given way to optimal criteria such as mini mum energy, minimum cost, and minimum time  operation. Optimization of these criteria makes it even more difficult to avoid dealing with unpleasant nonlinearities. Optimal control theory often dictates that nonlinear time-varying control laws are used, even if the basic system is linear and time-invariant.

The continuing advances in computer technology have had three principal effects on the controls field. One of these relates to the gigantic supercomputers. The size and the class of the problems that can now be modeled, analyzed, and controlled are considerably large than they were when the first edition of this book was written.

The second impact of the computer technology has to so with the proliferation and wide availability of the microcomputers in homes and I the work place, classical control theory was dominated by graphical methods because at the time that was the only way to solve certain problems, Now every control designer has easy access to powerful computer packages for systems analysis and design. The old graphical methods have not yet disappeared, but have been automated. They survive because of the insight and intuition that they can provide, some different techniques are often better suited to a computer. Although a computer can be used to carry out the classical transform-inverse transform methods, it is used usually more efficient for a computer to integrate differential equations directly.

The third major impact of the computers is that they are now so commonly used as just another component in the control systems. This means that the discrete-time and digital system control now deserves much more attention than [FS:PAGE]it did in the past.

Modern control theory is well suited to the above trends because its time-domain techniques and its mathematical language (matrices, linear vector spaces, etc.) are ideal when dealing with a computer. Computers are a major reason for the existence of state variable methods.

Most classical control techniques were developed for linear constant coefficient systems with one input and one output (perhaps a few inputs and outputs). The language of classical techniques is the Laplace or Z-transform and transfer functions. When nonlinearities ad time variations are present, the very basis for these classical techniques is removed. Some successful techniques such as phase-plane methods, describing function s, and other ad hoc methods, have been developed to alleviant this shortcoming.

However, the greatest success has been limited to low-order systems. The state variable approach of modern control theory provides a uniform and powerful method of representing systems of arbitrary order, linear or nonlinear, with time-varying or constant coefficient. It provides an ideal formulation for computer implementation and is responsible for much of the progress in optimization theory.

Modern control theory is a recent development in the field of control. Therefore, the name is justified at least as a descriptive title. However, the foundations of modern control theory are to be found in other well-established fields. Representing a system in terms of state variables is equivalent to the approach of Hamiltonian mechanics, using generalized coordinates and generalized moment. The advantages of this approach have been well-known I classical physics for many years. The advantages of using matrices when dealing with simultaneous equations of various kinds have long been appreciated in applied mathematics. The field of linear algebra also contributes heavily to modern control theory. This is due to the concise notation, the generality of the results, and the economy of thought that linear algebra provides.

Mechanism of Surface Finish Production

There are basically five mechanisms which contribute to the production of a surface which have been machined. There are:

(1) The basic geometry of the cutting process. In, for example, single point turning the tool will advance a constant distance axially per revolution of the work piece and the resultant surface will have on it, when viewed perpendicularly to the direction of tool feed motion, a series of cusps which will have a basic form which replicates the shape of the tool in cut.

(2) The efficiency of the cutting operation. It has already been mentioned that cutting with unstable built-up-edges will produce a surface which contains hard built-up-edge fragments which will result in a degradation of the surface finish. It can also be demonstrated that cutting under adverse conditions such as apply when using large feeds small rake angles and low cutting speeds, besides producing conditions whi[FS:PAGE]ch continuous shear occurring in the shear zone, tearing takes place, discontinuous chips of uneven thickness are produced, and the resultant surface is poor. This situation is particularly noticeable when machining very ductile materials such as copper and aluminum.

(3) The stability of the machine tool. Under some combinations of cutting conditions: work piece size , method of clamping, and cutting tool rigidity relative to the machine tool structure, instability can be set up in the tool which causes it to vibrate. Under some conditions the vibration will built up and unless cutting is stopped considerable damage to both the cutting tool and work piece may occur. This phenomenon is known as chatter and in axial turning is characterized by long pitch helical bands on the work piece surface and short pitch undulations on the transient machined surface.

(4) The effectiveness of removing sward. In discontinuous chip production machining, such as milling or turning of brittle materials, it is expected that the chip (sward) will leave the cutting zone either under gravity or with the assistance of a jet of cutting fluid and that they will not influence the cut surface in any way. However, when continuous chip production is evident, unless steps ate taken to control the swarf it is likely that it will impinge on the cut surface and mark it. Inevitably, this marking beside a looking unattractive, often results in a poorer surface finishing,

(5) The effective clearance angle on the cutting tool. For certain geometries of minor cutting edge relief and clearance angles it is possible to cut on the major cutting edge and burnish on the minor cutting edge. This can produce a good surface finish but, of course, it is strictly a combination of metal cutting and metal forming and is not to be recommended as a practical cutting method. However, due to cutting tool wear, these conditions occasionally arise and lead to a marked change in the surface characteristics.

Surface Finishing and Dimensional Control

Surface finishing many sometimes become an intermediate step processing. For instance, cleaning and polishing are usually essential before any kind of plating process. Some of the cleaning procedures are also used for improving surface smoothness on mating parts and for removing burrs and sharp corners, which might be harmful in later use. Another[FS:PAGE] important need for surface finishing is for corrosion protection in a variety of environments. The type of protection procedure will depend largely upon the anticipated exposure, with due consideration to the material being protected and the economic factors involved.

Satisfying the above objectives necessitates the use of main surface-finishing methods that involve chemical change of the surface mechanical work affecting surface properties, cleaning by a variety of methods, and the application of protective coatings, organic and metallic.

In the early days of engineering, the mating of parts was achieved by machining one part as nearly as possible to the required size, machining the mating part nearly to size, and then completing its machining, continually offering the other part to it, until the desired relationship was obtained. If it was inconvenient to offer one par to the other part during machining, the final work was done at the bench by a fitter, who scraped the mating parts until the desired fit was obtained, the fitter therefore being a ‘fitter’ in the literal sense. It is obvious that the two parts would have to remain together, and in the event of one having to be replaced, the fitting would have to be done all over again. I n these days, we expect to be able to purchase a replacement for a broken part, and for it to function correctly without the need for scraping and other fitting operations.

When one part can be used ‘off the shelf’ to replace another of the same dimension and material specification, the parts are said to be interchangeable. A system of interchangeability usually lowers the production costs as there is no need for an expensive, ‘fiddling’ operation, and it benefits the customer in the event of the need to replace worn parts.

Limits and Tolerances

Machine parts are manufactured so they are interchangeable. In other words, each part of a machine or mechanism is made to a certain size and shape so it will fit into any other machine or mechanism of the same type. To make the part interchangeable, each individual part must be made to a size that will fit the mating part in the correct way. It is not only impossible, but also impractical to make many parts to an exact size. This is because machines are not perfect, and the tools become worn. A slight variation from the exact size is always allowed. The amount of this variation depends on the kind of part being manufactured. For example, a part might be made 6 in. long with a variation allowed of 0.003(three thousandths) in. above and below this size. Therefore, the part could be 5.997 to 6.003 in. and still be the correct size. These are known as the limits. The difference between upper and lower limits is called the tolerance.

A tolerance is the total permissible variation in the size of a part.

The basic size is that size from which limits of size are derived by the application of allowances and tolerances.

Sometimes the limit is allowed in only one [FS:PAGE]direction. This is known as unilateral tolerance.

Unilateral tolerancing is a system of dimensioning where the tolerance (that is variation) is shown I only one direction from the nominal size. Unilateral tolerancing allow the changing of tolerance on a hole or shaft without seriously affecting the fit.

When the tolerance is in both directions from the basic size, it is known as a bilateral tolerance (plus and minus).

Bilateral tolerancing is a system of dimensioning where the tolerance (that is variation) is split and is shown on either side of the nominal size. Limit dimensioning is a system of dimensioning where only the maximum and minimum dimensions are shown. Thus, the tolerance is the difference between these two dimensions.

Introduction of Machining of:

Machining as a shape-producing method is the most universally used and the most important of all manufacturing processes. Machining is a shape-producing process in which a power-driven device causes material to be removed in chip form. Most machining is done with equipment that supports both the work piece and cutting tool although in some cases portable equipment is used with unsupported work piece.

Low setup cost for small quantities. Machining has two applications in manufacturing. For casting, forging, and pressworking, each specific shape to be produced, even one part, nearly always has a high tooling cost. The shapes that may be produced by welding depend to a large degree on the shapes of raw material that are available. By making use of generally high cost equipment but without special tooling, it is possible, by machining, to start with nearly any form of raw material, so long as the exterior dimensions are great enough, and produce any desired shape from any material. Therefore, machining is usually the preferred method for producing one or a few parts, even when the design of the part would logically lead to casting, forging or pressworking if a high quantity were to be produced.

Close accuracies, good finishes. The second application for machining is based on the high accuracies and surface finishes possible. Many of the parts machined in low quantities would be produced with lower but acceptable tolerances if produced I high quantities by some other process. On the other hand, many parts are given their general shapes by some high quantity deformation process and machined only on selected surfaces where high accuracies are needed. Internal threads, for example, are seldom produced by any means other than machining and small holes in pressworked parts may be machined following the pressworking operations.

现代的控制理论简介

下列几方面为现代控制理论发展的促进因素:

1.处理更多的现实模型系统的必要性

2.强调向最佳的控制和最佳的系统设计的升级

3.数字化计算机技术的持续发展.

4.当前技术的不成熟.

众所周知的方法在其它知识领域的适用性得到承认.

从容易解决的简单近似的模型到更多的现实模型的转变产生了两种效果：首先，模型必须包括很多的变量。其次，一个十分逼真的模型是尽可能[FS:PAGE]的包括非线性和随时间变化的参数。早先的忽略了系统的一些方面，例如很有可能的一方面就是在环境中有着反馈的交互作用。

在现代科技高度发达的社会，存在一种非常雄心的目标的趋势，这也意味着要处理有着很多相互关联成分的复杂系统，高精确度与高效率的需要改变了控制系统的执行重点。在超频百分比，时间设置，频宽等等方面的经典规范，在很多情况下解决了优化标准如最小能量，最小花费，最小时间控制，优化这些标准时很难避免和不开心的非线性打交道。即使基础系统是线性的和不随时间变化的，优化控制理论显示非线性时间变化控制也被应用到了。

不停发展的计算机技术在控制领域创造了三条最重要的影响。其中一项是有关数字化的超级计算机，较之这本书首印时期，现在能模拟，分析，控制的问题的大小和种类都要大得惊人。

计算机技术的第二个问题就是必须处理微型计算机在家庭和工作地的扩散与广泛的可靠性。古典的控制理论是以图画似的方法为主导的. 因为在时间那是唯一的解决确定的问题的途径。为了系统分析和设计,现在每一个控制设计者很容易有机会接近强大的计算机内部。老的图画似的方法不但没有消失, 并且还使其自动化了.它们之所以能生存是因为提供了洞察力与直觉，许多不同的技术经常能更适合于计算机。虽然计算机能被用于执行经典的改变-到转的改变方法，但它通常更多的有效用于直接整合微分方程。

计算机的第三个，也是最重要的方面，就是它们现在已经如此普遍地应用于控制系统，俨然其中的一员。其价格，型号和稳定性使得能够在许多系统中常规的使用。这也意味着离散的-时间和数字的系统控制现在比在它过去更受人关注。

现代的控制理论更适合上面的趋势. 因为它的时间-领域技术和它的数学的语言(公式, 线性向量空间, 等等.) 是处理计算机时的方法。. 计算机是状态变量方法存在的主要原因。

最多的古典的控制技术是为了发展只有一个输入和一个输出(或许少许输入和输出)线性常数系数系统. 古典的技术的语言是拉普内斯或Z-改变和传送功能. 就在那个时候非线性和时间变量出现了, 这些古典的技术的基础远离了. 一些成功的技术例如阶段-平面方法, 描述函数, 和其他的特别方法,发展并缓和了这些缺点。然而, 最大的成功被这些低级命令系统限制了. 现代的控制理论的状态变量接近供应统一和强大的方法表现任意的订购的系统, 线的或非线性的, 有时间-改变或常数系数.它为形成计算机的执行提供了理论，同时也对大多数优化理论的进程负有责任。

现代的控制理论是在控制领域的最近发展. 因此, 这个名字至少替换了一个描述性的标题. 然而, 现代的控制理论的基础在其它已知领域也被发现了. 用一般化坐标和一般化瞬间表现一个系统时，在相关状态变量上，其等同到接近哈密尔敦函数机械学,. 这接近的优势在古典的物理学已经闻名了许多年. 应用数学领域中，在处理各种形式相类似的方程时，利用母式的优越性早已表现出来了，线性代数学也很大程度上归功于现代的控制理论。 这是由于线性代数学所提供的简明的符号, 结果的普遍性, 和思考的效率。

表面粗糙度的技术

在已经进行机械加工过的表面，有五种基本的影响其表面粗糙度的技术。

1、切断过程的基本几何学. 例如，在单点车削时，工件每转一周，刀具就沿轴线方向进给一个固定的距离。从垂直刀具进给的方向观察，所得到的表面上有很多尖角，这些尖角的形状与切削刀具的形状相同。

2、切断操作的效率. 已经提过的用不稳定的切削瘤切削将会加工出包含有坚硬的切削瘤碎片在上面的表面，而这些将会导致表明粗糙度的等级降低。已经证明，在采用进给量大，前角小，切削速度低的不利情况下，除了产生不稳定的切削瘤外，切削过程也会不稳定。同时，在切削区里进行的也不再是切削，而是[FS:PAGE]撕裂，导致厚度不均匀，不连续的切削，加工出的表面质量差。在切削加工延展性良好的金属材料，如铜和铝时，这种情况就尤为突出。

3、机械工具的稳定性。在许多联合切削的情况下：工件的大小，夹紧的方法，和切断工具相对于机床结构的坚硬度，不稳定性是建立在使其变化的工具上的。在某些情况下，这种变化将达到并保持很长一段时间，在另外一些情况下，这种变化将会产生，除非切断停止，否则，将肯定会同时对切断刀具和工具产生破坏。这种现象就是知名的刀振，在轴向转动被描述为在工件表面的长间距螺旋状带和段间距波动在机械加工的过渡表面。

4、刀刃的移动效率。在不连续的产品加工过程中例如易碎材料的磨或旋转，我们期望碎片在重力作用或在冷却液的喷射作用下将离开切削面域。而且怎么也不会影响切削表面。然而，在连续切削时，产品是明显的，除非逐步控制刀刃，否则他很有可能中级切削表面并在其上留下记号。不可避免，这记号在旁边样子不美的, 时常导致差的表面粗糙度。

5、切断工具的有效清除角。由于副切削刃的某种几何特征减轻和清除了角，使得在主切削面上主切削刃切削和副切削刃打磨变得可能。这样能加工出良好的表面粗糙度，但是，当然，它严格来讲，是一种金属切削和金属成型的综合，而不失被认为的一种实际的切削方法。然而，归功于切削工具的表面处理，这些情况偶尔才会出现，并导致了表面特性的标志性改变。

表面精整加工与尺寸控制

产品在被加工成它们的适当的外形和大小时，经常地需要各种的表面精整加工，使得其能够比较令人满意地履行它们的功能. 在一些情况下，通过提高材料表面的物理特性来抵抗腐蚀和磨损是非常重要的。在许多制造过程中，产品表面上都残留有污垢，碎屑，油渍以及其它有害的材料。假设那是由不同种金属材料，或是由同一种金属材料在不同的加工方式中所造成的，大多数需要一些特殊的表面处理技术来提供均匀的外表面。

有时表面精整加工也许只是中间阶段处理，例如，清洁的和磨光在任何一种电镀之前都是必不可少的工序。有些清洁程序是为了改善配合处表面的光滑程度，或是清除会对稍候工序产生有害作用的毛刺和尖角。表面精整加工的另一重要需要就是为了在各种各样的环境下防腐蚀。这种保护程序很大程度上依赖于预期的暴露，考虑到材料将被保护和其所包含的经济因素。

满意于上表面材料使应用主要表面精整技术成为必然性，而这技术包括材料工作表面特性在化学上的改变，用各种方法清洗，以及有机的和金属的保护膜的应用。

在早期的工程中，零部件的装配是这样完成的：加工一个部件使其尽可能的达到要求的大小，加工装配部件接近大小时，也就完成了它的加工，继续提供另一部件，直到获得所要求的配合关系。如果在加工一个部件时不方便提供另一部件，那么最后的工作将交予装配工完成，它刮削装配部件直到获得要求的配合。因此，装配工也就成为了“fitter”在字面上的意思了。很显然，这两部件将必然保持在一起，最重要的是其中一个具有互换性，装配也将全部重新完成。在这期间，我们希望能更换一个已经坏掉了的零件，并且在不需要刮磨和其它装配作业的情况下就能具有原有功能。

如果一个部件能被用作为备用件去替换另一格同样尺寸和材料特性的零件，那么我们就说它具有互换性。具有互换性的系统经常可以减少其产品成本，因此，对于一种昂贵的，琐细的加工工艺没有必要存在。而且万一假使顾客有必要更换磨损了的零部件。

大批量生产的零部件都具有可互换性。也就是说，一部机器或一个系统的每一个零部件都做成确定的大小和规格，因此它们将用于装入于同类型的其它机器或系统。为了使零部件具有互换性，每个单个零件都必须做成可以与其配件能正确装配。把每个零件做成确切的大小，[FS:PAGE]那不但没有必要，也是不切实际的。这是因为机器不时完美无缺的，加工工具也会在加工过程中逐渐损耗。在允许范围内稍微的尺寸变动经常是允许的。而这个变动的范围是由要进行制造的零件所决定的。例如，一个零件要做成6英寸大小，长度变化范围是正负0.003英寸。因此，这个零件制成5.997英寸或者6.003英寸都符合正确的尺寸要求。这就是极限。上限尺寸与下限尺寸之间的大小就是公差。公差就是零件大小尺寸总的允许变动量。

基本尺寸就是那样的尺寸，从基本尺寸出发，应用极限和公差来得到(推导出)尺寸极限。

有时候极限允许值存在于一个方向，这就是所谓的单边公差。

单边公差标注是一种只表现在标称大小的单方向的尺寸标注制度，它允许在没有严重影响配合的前提下来改变孔或轴的公差。

当公差是基本尺寸向两侧延伸时，这时就变成了双向公差（正或负）。

双向公差标注是一种当公差在分离或者表现与标称尺寸两侧时的尺寸标注制度。极限尺寸标注就是一种在仅仅表现出尺寸的最大值或最小值是的尺寸标注制度。因此，公差就是在这两种尺寸之间的距离。

机器加工的介绍

作为一种成型方法，机械加工得到了普遍应用并且成为了机械制造过程中最重要的部分。机械加工是一种在动力驱动下使材料以碎屑的方式分离的成型方法。尽管在某些场合，工件无支撑情况下，使用移动式装备来实现加工，但大多数的机械加工还是通过既支承工件又支承刀具的装备来完成。

小批量的安装成本。机械加工在机械制造中有两种应用形式。为铸造，锻造和压力加工等的特种成型制造，仅仅只是一个零部件，几乎经常达到了刀具的高花费。这些外形可能是焊接而成的，它很大程度上取决于可利用的原材料的外形。一般来说，通过利用高价设备而又无需特种加工条件下，几乎可以从任何种类原材料开始，借助机械加工把原材料加工成任意所要求的结构现状，只要外部尺寸足够大，那都是可能的。

严密的精度，合适的表面粗糙度。机械加工的另一个应用就是基于高精度和表面精整处理上的。对于虽低但可以接受的公差，许多小批量加工的零件可以利用其它的方法来大批量的生产。另一方面，许多零部件的外形是由在所选的需要高精度的表面经过大量的机械加工所形成的。例如内孔，很少是由除了机械加工以外的方法加工的，压力加工零件上的小孔，也许就是在压力加工操作之后的机械加工出来的。

In addition to producing high quality radiographs, the radiographer must also be skilled in radiographic interpretation. Interpretation of radiographs takes place in three basic steps which are (1) detection, (2) interpretation, and (3) evaluation. All of these steps make use of the radiographer's visual acuity. Visual acuity is the ability to resolve a spatial pattern in an image. The ability of an individual to detect discontinuities in radiography is also affected by the lighting condition in the place of viewing, and the experience level for recognizing various features in the image. The following material was developed to help students develop an understanding of the types of defects found in weldments and how they appear in a radiograph.

Discontinuities

Discontinuities are interruptions in the typical structure of a material. These interruptions may occur in the base metal, weld material or "heat affected" zones. Discontinuities, which do not meet the requirements of the codes or specification used to invoke and control an inspection, are referred to as defects.

General Welding Discontinuities

The following discontinuities are typical of all types of welding.

Cold lap is a condition where the weld filler metal does not properly fuse with the base metal or the previous weld pass material (interpass cold lap). The arc does not melt the base metal sufficiently and causes the slightly molten puddle to flow into base material without bonding.

Porosity is the result of gas entrapment in the solidifying metal. Porosity can take many shapes on a radiograph but often appears as dark round or irregular spots or specks appearing singularly, in clusters or rows. Sometimes porosity is elongated and may have the appearance of having a tail This is the result of gas attempting to escape while the metal is still in a liquid state and is called wormhole porosity. All porosity is a void in the material it will have a radiographic density more than the surrounding area.

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Cluster porosity is caused when flux coated electrodes are contaminated with moisture. The moisture turns into gases when heated and becomes trapped in the weld during the welding process. Cluster porosity appear just like regular porosity in the radiograph but the indications will be grouped close together.

Slag inclusions are nonmetallic solid material entrapped in weld metal or between weld and base metal. In a radiograph, dark, jagged asymmetrical shapes within the weld or along the weld joint areas are indicative of slag inclusions.

Incomplete penetration (IP) or lack of penetration (LOP) occurs when the weld metal fails to penetrate the joint. It is one of the most objectionable weld discontinuities. Lack of penetration allows a natural stress riser from which a crack may propagate. The appearance on a radiograph is a dark area with well-defined, straight edges that follows the land or root face down the center of the weldment.

Incomplete fusion is a condition where the weld filler metal does not properly fuse with the base metal. Appearance on radiograph: usually appears as a dark line or lines oriented in the direction of the weld seam along the weld preparation or joining area.

Internal concavity or suck back is condition where the weld metal has contracted as it cools and has been drawn up into the root of the weld. On a radiograph it looks similar to lack of penetration but the line has irregular edges and it is often quite wide in the center of the weld image.

Internal or root undercut is an erosion of the base metal next to the root of the weld. In the radiographic image it appears as a dark irregular line offset from the centerline of the weldment. Undercutting is not as straight edged as LOP because it does not follow a ground edge.

External or crown undercut is an erosion of the base metal next to the crown of the weld. In the radiograph, it appears as a dark irregular line along the outside edge of the weld area.

Offset or mismatch are terms associated with a condition where two pieces being welded together are not properly aligned. The radiographic image is a noticeable difference in density between the two pieces. The difference in density is caused by the difference in material thickness. The dark, straight line is caused by failure of the weld metal to fuse with the land area.

Inadequate weld reinforcement is an area of a weld where the thickness of weld metal deposited is less than the thickness of the base material. It is very easy to determine by radiograph if the weld has inadequate reinforcement, because the image density in the area of suspected inadequacy will be more (darker) than the image density of the surrounding base material.

Excess weld reinforcement is an area of a weld, which has weld metal added in excess of that specified by engineering drawings and codes. The appearance on a radiograph is a localized, lighter area in the weld. A visual inspection will easily determine if the weld reinforcement is in excess of that specified by the individual code involved in the inspection.

Cracking can be detected in a radiograph only the crack is propagating in a direction that produced a change in thickness that is parallel to the x-ray beam. Cracks will appearas jagged and often very faint irregular lines. Cracks can sometimes appearing as "tails" on inclusions or porosity.

Discontinuities in TIG welds

The following discontinuities are peculiar to the TIG welding process. These discontinuities occur in most metals welded by the process including aluminum and stainless steels. The TIG method of welding produces a clean homogeneous weld which when radiographed is easily interpreted.

Tungsten inclusions. Tungsten is a brittle and inherently dense material used in the electrode in tungsten inert gas welding. If improper welding procedures are used, tungsten may be entrapped in the weld. Radiographically, tungsten is more de[FS:PAGE]nse than aluminum or steel; therefore, it shows as a lighter area with a distinct outline on the radiograph.

Oxide inclusions are usually visible on the surface of material being welded (especially aluminum). Oxide inclusions are less dense than the surrounding materials and, therefore, appear as dark irregularly shaped discontinuities in the radiograph.

Discontinuities in Gas Metal Arc Welds (GMAW)

The following discontinuities are most commonly found in GMAW welds.

Whiskers are short lengths of weld electrode wire, visible on the top or bottom surface of the weld or contained within the weld. On a radiograph they appear as light, "wire like" indications.

Burn through (icicles) results when too much heat causes excessive weld metal to penetrate the weld zone. Lumps of metal sag through the weld creating a thick globular condition on the back of the weld. On a radiograph, burn through appears as dark spots surrounded by light globular areas.

The Seven Steps To A Quality Gating Design

第一步确定铸件质量等级。这样就设定了浇口设计目标。没有充分了解客户对此零件的所有要求就不可能设计出良好的浇口体系。

Step 1. Determine the casting quality levels. This sets the goals for the gate design. It is not possible to design a good gating system without knowing as intimately as possible all the customer requirements for this part.

第二步根据质量等级确定工艺限制。意思是说与浇口设计互相影响的工艺因素的等级在确定时要考虑客户所提供的质量等级。工艺因素在浇口设计中不是独立的，而必须考虑浇口的设计效果。

Step 2. Define the process limits based on the quality levels. This means that the levels for the process factors that interact with the gate design will be defined in consideration of the quality levels provided by the customer. The process factors are not independent of the gate design, and must be considered in the gate design effort.

第三步 PQ2分析计算。一旦把工艺限制确定下来，就可以使用PQ2 计算法来决定之后计算的浇口面积。也可以用来确定所选的操作条件, 以及特别浇口设计这样一个操作变量所允许的范围。也再次说明操作条件不是浇口设计中独立存在的。

Step 3. Run the PQ2 calculations. Once the process limits are set, then the PQ2 calculations can be run to determine the gate area for later calculations, and also to define the selected operating conditions and the allowable range for the operating variables for this particular gate design. Again, the operating conditions are not independent of the gate design.

第四步确定流型和浇口位置。这是基于早期开发的质量考虑。开发出的流型要与铸件的质量要求相一致，而且要设定浇口的入水位才可以开发出流型(可以尽量多地利用零件的外观)。

Step 4. Define the flow pattern and the gate locations. This is based on the quality considerations developed earlier. The flow pattern is developed to match the quality needs of the casting, and the gate entrances are set to develop the flow pattern (as much as can be done with the part configuration).

第五步设计浇口。浇口设计要设定浇口的位置和形状。这种设计特别用来产生先前步骤确定的流型。

Step 5. Design the gates. The gate design will set the location and the shape of the gates. This design is developed specifically to generate the flow pattern determined in the previous steps.

第六步设计横浇道系统。开发横浇道系统的形状，它必须支持在第五步中开发出的浇口设计。如果需要的话，可以使用模拟软件(然而，在没有作第1-5步的情况下不应使用模拟，特别是第1-3步)。

Step 6. Design the runner system. Develop the shape of the runner system, which must support the gate design developed in step 5. If needed, simulation software is used at this point (simulation should NOT be used without doing steps 1-5, and especially steps 1-3), however.

第七步设计排气和溢流系统。要得到优质的铸件，整个系统的这一部分是非常重要的，而且在设计浇注系统时应视为同样优先考虑的事和值得注意的事项。

Step 7. Design the Vent and overflow system. This part of the system is essential to achieving quality castings, and should be given the same priority [FS:PAGE]and attention as designing the gating system.