锌合金拉链头压铸缺陷的模拟分析与工艺改进

Simulation Analysis of Die-casting Defects and Process Optimization for Zipper Head of Zn Alloy

利用Flow-3D软件对锌合金拉链头的压铸缺陷进行了数值分析。结果表明,原始压铸工艺会产生卷气和表面流痕缺陷。原工艺内浇道尺寸偏小,金属液在充填型腔时产生旋涡,最终造成卷气。流痕区域金属液的温度和流动速度明显高于周边区域,表明该流痕是由于温度场和速度场不均匀引起的,实际流痕位置与模拟结果一致。通过增加内浇道长度,提高模具温度和金属液浇注温度,可防止产生旋涡,并使温度场和速度场均匀,有利于消除表面流痕缺陷。

The Flow-3D sottware was used to analyze the die casting defects of Zn-alloy zipper head. The simulation results show that the casting defects of air entrainment and flow mark are formed with the initial gating system because of small ingate size, resulting in vortex formed and air entrained during molten metal filling cavity. The temperature and filling velocity in the flow mark area are higher than vicinity, which causes the flow mark defect. The flow mark shape and position in simulation results are consistent with actual production results. By enlarging the ingate size and increasing mould temperature and pouring temperature, the temperature and velocity field can become homogeneous, which are effective to eliminate air entrainment and flow mark defects.