材料期刊网

ZA8锌合金以其卓越的耐冲击性能和尺寸稳定性，在精密电子类产品中得到广泛的应用．但这种合金材料的热流动性能较差，在其压铸成型中会造成很多的压铸缺陷．为减少薄壁ZA8锌合金铸件压铸生产中出现的流纹、缩松、气孔、起泡等缺陷，本文在采用传统的锌合金压铸流道实验的基础上，调节各种工艺参数，对其产生的压铸缺陷进行了统计分析．分析结果显示，流道结构是该铸件缺陷产生的主要原因，改用热流道辅助压铸成型．重新统计后发现，热流道能有效地减少铸件出现的各种缺陷，且材料利用率可以从30．6％提高到41．9％．在对比压铸传统流道和热流道特点的基础上，给出了热流道的设计和安装结构，详细阐述了压铸热流道技术的原理，分析了采用压铸热流道技术所带来的经济效益．研究得出，锌合金压铸热流道相比于传统的流道，在生产中具有加温时间快、产品成型周期短、温度压力损失小、材料利用率高、铸件缺陷低等优点．

ZA8 zinc alloy materials exhibiton wide applications in precision electronic products due to their excellent impact resistance and dimensional stability. However, the poor thermal flow performance of these materials can cause the formation of numerous die casting defects during die casting processing. In order to reduce the casting defects such as flow lines, porosity, shrinkage and blister, statistical analysis of the casting defects, assistanted with traditional die casting runner experiments and process parameter modification of zinc alloys, was performed in this study. The obtained results indicated that the improper runner can result in the formation of casting defects. The statistical analysis showed that the amount of casting defects significantly decreases, and the material utilization increases from 30.6% to 41.9% after adopting a hot runner structure. After comparative study of the features of the traditional runner and hot runner, the structure of the hot runner was optimized. The principles and economic benefits of the hot runner were analyzed in details. Compared with the traditional runner for the die casting of zinc alloys, the hot runner possess the following advantages as faster heating times, shorter molding cycles, lower temperature and pressure losses, higher material utilization, and fewer casting defects.