上海第一缝纫机厂生产JA型缝纫机梭心套壳的绞孔工序,过去是在专用的手工进给车床上分三个工步,钻定位锥孔、挖孔、精锪底平面的机械加工(见图1)。不但生产效率低,劳动强度高,材料的利用率仅有14%,而且在最后经渗碳淬火,变形量较难控制。为此,我厂采取了“三结合”的方法,试验以冷挤压一次成形的新工艺来代替金属切削加工。我们在战无 Shanghai first sewing machine factory production JA sewing machine bobbin shell reaming process, the past is in a dedicated manual feed lathe on three steps, drill positioning conical hole, digging holes, fine bottom plane machining see picture 1). Not only low production efficiency, high labor intensity, material utilization rate of only 14%, but also in the final by carburizing and quenching, deformation is more difficult to control. To this end, I plant adopted a “triple combination” approach to test a cold extrusion forming a new process to replace metal cutting. We are at war