注塑成型充填/后充填过程统一的可压缩流动分析

A unified compressible flow analysis of filling and post-filling in injection molding

注塑成型是重要的塑料成型工艺,成型过程中熔体在模腔中的流动和传热对最终制品的性能和质量有重要的影响,因此,精确预测注塑过程的流动及传热历史,并进一步预测注塑制品的收缩、翘曲和机械性能等性能和质量指标具有重要意义。为了精确地描述成型过程中材料的流动及传热行为,本文针对注塑成型过程的工艺特点,将充填后充填过程作为一个统一的过程,考虑材料可压缩性及相变对充填和后充填过程的影响,建立了充填后充填过程的统一数学模型。采用有限元/有限差分/控制体积混合数值方法,实现了注塑成型充填后充填一体化模拟。数值模拟结果与实验结果的对比,验证了本文模型和算法。

Injection molding is one of the most important processes for producing thin thermoplastic parts, and the molding processes have important effects on the final properties and quality of the injection-molded parts. It is significant to predict the history of flow and heat transfer of injection molding accurately and thus predict the part quality and properties such as shrinkage, warpage and mechanical properties. In this paper, the flow and heat transfer of filling and post-filling stage were considered as a unified process based on the process characteristics of injection molding, and the unified model was built considering the effects of compressibility and phase change of polymer material in order to describe the flow and heat transfer behavior more accurately. A hybrid Finite element/Finite difference/Control volume method was employed to implement the numerical simulation of such unified theoretical model. Comparison of numerical results and experimental results verified the theoretical model and numerical algorithm in this paper.