锌合金拉链头压铸缺陷分析与工艺优化

Analysis of Defects and Process Optimization of Die Casting Zn Alloy Zipper Head

利用Flow-3D软件对锌合金拉链头的热室压铸成形工艺进行了优化设计。通过模拟分析发现,原压铸工艺会使金属液进入型腔后产生绕流,进而发展为旋涡,最终产生卷气缺陷。数值分析预测的卷气位置与压铸件的实际缺陷一致,并通过金属液流动速度矢量图说明了旋涡产生的原因。采用发散式横浇道和内浇口结构后,金属液充型时不会直接冲刷型腔侧面,可以有效避免金属液在充型过程中产生旋涡,消除了卷气缺陷。

The Flow-3D software was employed to optimize the hot-chamber die casting process of die casting Zn alloy zipper head. The simulation results show that detour flow and vortex are formed during molten metal filling the cavity in the initial gating system, and gas-entrapment in parts can be generated. The gas-entrapment position from the simulated result is consistent with the practical product defects, and velocity vector of molten metal flow can be used to explain the formation of vortex. A new gating system was designed, in which the runner and ingate were diverged from sprue. The simulated results show that metal molten flow can not impact the side of the work cavity directly, effectively avoiding vor- tex flow and eliminating gas-entrapment in the die casting Zn alloy zipper head.