简述加工机器零件时,除了要有机床、刀具、量具及其它工具外,还要有各种机械加工用的夹具,以对工件进行定位和夹紧,保证工件的加工精度。随着工厂产品的发展,各种机器结构不断改进,产品零件也跟着更换.往往一些零件只生产3～4年或更短的时间,就被更新的零件所淘汰。若仍以一道工序配一套固定不变的专用夹具的生产方法,就无法适应生产发展的需要。专用夹具生产周期很长,一副中等复杂的夹具,通常需2～3个月才能生产出来。如某一新产品需数十至数百副夹具,等这些夹具全部生产出来时,这一新产品可能已过时。另外,专用夹具从 Brief description of the processing machine parts, in addition to have a machine tool, measuring tools and other tools, but also have a variety of mechanical processing fixture to locate and clamp the workpiece to ensure the accuracy of the workpiece processing. With the development of the factory’s products, the structure of various machines is continuously improved and the parts of the products are also replaced. Often, some parts are only manufactured in 3 to 4 years or less and are eliminated by the newer parts. If still a process with a fixed set of production methods for special fixtures, they can not adapt to the needs of the development of production. Special fixture production cycle is very long, a medium complex fixture, usually takes 2 to 3 months to produce. If a new product requires tens to hundreds of jigs, the new product may be out of date when all the jigs are manufactured. In addition, special fixture from