中英文对照机械专业英语文章

发布日期:[10-12-26 11:51:49] 浏览人次:[]

sufficiently the mold halves are opened at the mold parting plane and the parts ejected by a knockout system drop into a receiving bin below.

模具被紧紧地夹住以抵抗注塑压力,并在热塑性塑料的融化温度以下很好地冷却。当模腔内的零件充分冷却,剖分模在模具分模面处打开,推出系统将零件推出落入下面的接收容器内。

This summarizes the overall cycle, but leaves out much vital detail that is necessary for understanding the process. However, with this introduction, it is possible to understand the advantages and disadvantages of the process.

这概述了整个循环,但省略了许多对理解此工艺所必需的很重要细节。然而通过本介绍,了解这种工艺的优缺点仍是可能的。

Effects of Process Variables on Orientation  

加工变量对方向性的影响

In injection molding, any variation in processing that keeps the molding resin hot throughout filling allows increased  relaxation and, therefore, decreased  orientation. Some of the steps that can be taken to reduce orientation are as follows.

在注塑成型时,整个填料过程始终保持成型树脂高温的任何加工变化都会增加松弛作用而减少方向性。下面是可以用于减少方向性的若干措施。

Faster injection (up to a point): less  cooling during filling, hence a thinner initial  frozen layer, lower viscosity due to shear  thinning; better flow to corners; and less   crystallinity all favor lower subsurface orientation. The primary effect is that the gate will freeze more quickly. At that point, orientation stops and relaxation starts.

较快注塑(到点):在填料过程中冷却较少,因此初始固化层较薄,由于剪应变稀少而粘性较低;能较好地流到角落;结晶度较小;所有这些促成表面下的方向性也较低。主要效果是闸道将较快固化。这样使得方向性停止产生而松弛作用开始增加。

Higher melt and mold temperatures: lower  melt viscosity, easier filling, and greater relaxation favor reduced orientation.

Reduced packing time and pressure: overpacking inhibits relaxation processes.

较高的融化和成型温度:融化粘性较低,更容易填充,较大松弛作用促成方向性减少。

减少挤压时间和压力:过度挤压会抑制松弛过程。

Reduced gate size: larger gates take longer to freeze off and permit increased orientation.

减小闸道尺寸:闸道越大则固化时间越长并会使方向性增加。

Excessively high injection speed can cause high surface orientation and increase susceptibility to stress cracking. For example, moldings that are to be electroplated, and will be subject to acid solutions during plating, must be made using very slow injection speeds to  minimize surface orientation.

过高的注塑速度会引起较高的表面方向性及增加应力破裂的敏感性。例如,要电镀的注塑件在电镀时会经受酸溶液,必须采用很低的注塑速度制造以使表面方向性最小化。

On the other hand, the transverse motion component of the melt front in most moldings can cause transverse subsurface orientation superimposed on the primary orientation, giving a desirable biaxial orientation effect.

另一方面,大多数注塑件的融化前部横向运动部分能导致在主要方向性上有层理的表面下横向方向性,产生需要的双轴方向性效应。

Orientation c

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