Engineering drawing is the common language by which draftspersons, tool designers, and engineers indicate to the machinist and toolmaker the physical requirements of a part. Drawings are made up of a variety of lines, which represent surfaces, edges, and contours of a workpiece. By adding symbols, dimension lines and sizes, and word notes, the draftsperson can indicate the exact specifications of each individual part.www.mapeng.net马棚网机械资讯

A complete product is usually shown on an assembly drawing by the drafter. Each part or component of the product is then shown on a detailed drawing, which is reproduced as copies called prints. The prints are used by the machinist or toolmaker to produce the individual parts which eventually will make up the complete product.www.mapeng.net马棚网机械资讯

In order to describe the shape of no cylindrical parts accurately on a drawing or print, the draftsperson uses the orthographic view or projection method. The orthographic view shows the parts from three sides; the front, the top, and the right-hand side. These three views enable the draftsperson to describe a part so completely that the machinist knows exactly what is required.www.mapeng.net马棚网机械资讯

Cylindrical parts are generally shown on prints in two views: the front and the right side. However, if a part contains many details, it may be necessary to use the top, bottom, or left-side views to describe the part accurately to the machinist. www.mapeng.net马棚网机械资讯

In many cases, complicated interior forms are difficult to describe in the usual manner by a draftsperson. Whenever this occurs, a sectional view, which is obtained by making an imaginary cut through an object, is presented. This imaginary cut can be made in a straight line in any direction to best expose the interior contour or form of a part.www.mapeng.net马棚网机械资讯