目前中、小批多品种生产的工件品种已占工件种类总数的 85 %左右。现代生产要求企业所制造的产品品种经常更新换代 ,以适应市场激烈的竞争 ;另一方面 ,在多品种生产的企业中 ,约隔 4年就要更新 80 %左右的专用夹具 ,而夹具的实际磨损量仅为 1 5 %左右 ,因此需要有能装夹一组具 At present, small and large batches of varieties produced varieties of workpieces accounted for about 85% of the total number of parts. Modern production requires that the varieties of products manufactured by the enterprises should be constantly updated so as to meet the fierce competition in the market. On the other hand, about 80% of the special-purpose fixtures will be updated in the multi-variety enterprises in about 4 years, and the actual Wear is only about 15%, so there is a need to have a fixture