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由于活塞在铸造时,人工铸造既有外模,又有内芯及底芯,各处冷却速度不好控制,成品率只能达到92％,而由于底芯所致废品达5％。通过底芯下抽工艺的改进,使底芯引起的废品率降到0.1％,并且使底芯寿命提高了约6倍。 1.原铸造工艺分析 大活塞燃烧室较大,且起模斜度要求3°～5°,并且燃烧室尺寸及容积要求很严。原工艺是将底芯固定在台面板上,浇注一只活塞,需要拔出内芯及销轴,然后打开模具,活塞仍然吸附在底芯上,操作者只好敲打活塞取下。况且取下活塞的时间不好掌握。一个底芯铸3000只左右活
As the piston in the casting, the artificial casting of both the outer mold, but also the inner core and the bottom core, poor cooling rate control everywhere, the yield can only reach 92%, while the bottom core due to waste up to 5%. Through the bottom core pumping process improvements, the core caused by the scrap rate dropped to 0.1%, and the core life expectancy increased by about 6 times. 1. The original casting process analysis Big piston combustion chamber larger, and the draft required 3 ° ~ 5 °, and the combustion chamber size and volume requirements are very strict. The original process is fixed to the bottom core on the table, pouring a piston, the need to pull out the core and pin, and then open the mold, the piston is still attached to the bottom core, the operator had to knock the piston removed. Moreover, the time to remove the piston is not good grasp. A bottom core cast about 3000 live