计算机仿真技术在注塑成型浇口优化中的应用

Application of Computer Simulation Technology in Optimization of Injection Molding Gate

注塑成型后零件的体积收缩量是衡量成型质量的重要指标之一,在简述了注塑成型浇口设计对零件体积收缩量影响的基础上,提出了聚丙烯材料手机背壳的注塑仿真过程,以浇口位置、零件结构和浇口尺寸为影响因子,通过27次模拟实验分析它们对零件收缩情况的影响。结果表明,成型过程中型腔内塑料熔体的压力对收缩情况有较大影响,型腔内熔体的压力越大,体积收缩量越小;在浇口位置的选择中,应避开零件结构较为复杂的位置,对于结构较为简单的薄壳类零件可以将点浇口位置选择在壁厚较大处,以提高熔体流动速率并减小体积收缩量;增大浇口尺寸有利于减小熔体喷出时的压力损失,从而减小收缩变形量。

The volume shrinkage of the parts after injection molding was one of the important indexes to measure the molding quality. On the basis of describing the influence of the injection gate design on the volume shrinkage of the parts briefly, the injection molding simulation process of the polypropylene material back shell was proposed, the influence of the gate position, part structure and gate size on the shrinkage of the parts were analyzed by 27 simulation experiments. The results show that the pressure of the plastic melt in the cavity has great influence on the shrinkage during the forming process, the larger the pressure of the melt in the cavity, the smaller the volume shrinkage; in the choosing of the gate position, the part structure should be avoided. For more complicated positions, for thin-shell parts with simple structure, the position of the gate can be selected at a large wall thickness to improve the melt flow efficiency and reduce the volume shrinkage; increasing the gate size is advantageous in reducing the pressure loss when the meh is ejected, thereby reducing the amount of shrinkage deformation.