采用虚拟试验解决金属粉末注射成形制品的质量问题

Solution of Quality of Metal Injection Molding with Virtual Experiment

针对在金属粉末注射成形中,反复试模法优化工艺参数成本高、时间长的不足,通过扩充MoldFlowMPI软件中的材料数据库,对316L不锈钢合金模芯零件进行虚拟实验研究。研究结果表明,由于熔体流动的"跑道效应",当采用单浇口注射成形时,模芯两侧熔体流动严重不平衡,端面4个波峰和波谷明显,中部芯柱出现欠注,零件中间芯轴处成形最困难。通过优化单浇口位置、数量和零件的结构设计,采用对称双浇口设计方案解决了实际生产中存在的断裂、欠注和不良流动等质量问题。

To avoid the disadvantages, such as higher cost, and longer period of time, caused by the trying mold in optimizing processing parameters of metal injection molding (MIM), MoldFlow MPI was applied to MIM and virtual experiments for 316L stainless steel alloy mold core were carried out, which is realized through extending the database of MPI to MIM feedstock. The results show that because of ”Runway effect” , there is a serious disequilibrium flow on two sides in injection molding with a single gate, there are four obvious wave crests and troughs on flow front, there is short shot at central pole, and there is an area to most difficultly mold in the core axis. The quality problems of breakage, short shot and defective flow are solved by optimizing the single gate position, gate numbers and structure design of parts. Finally, the design scheme of symmetrically double gates is adapted and the developing efficiency is improved obviously.