微沟槽结构注塑成形的充型过程计算方法

微注塑成形制造方法适合于热塑性材料微小型器件大批量加工,对微注塑关键步骤——充型进行分析计算,有助于微注塑工艺参数和模具结构优化。目前研究表明,微尺度聚合物熔体流动与常规流动存在显著差异,采用常规尺度流动计算分析工具会带来较大偏差。本文以开源计算代码OpenFOAM为基础,综合由实验获得的熔体表面特性规律和粘度变化规律等,采用面向对象编程方法构建了熔体填充微结构型腔流动过程的计算模块,以微流体器件中的典型微结构——微沟槽注塑充型过程为例进行数值模拟,分析了表面力和粘度作用对其注塑充型填充率的影响。

Numerical simulation of filling in micro-channel injection molding

Micro injection molding is suitable for mass production of thermo-plastics-based micro- and mini- parts. Analyzing the filling process in micro-injection molding is useful and important for the optimization of fabrication process and molding master structure. But the results from researches indicate that distinct difference exists between micro-filling and macro-filling of polymer melt and it will obviously induce deviation in the evaluation of micro-filling with macro-scale analysis tools. In this paper, based on the open source code of OpenFOAM, an analysis module is constructed for the filling flow process of micro injection molding, in which the surface characteristic and the law for viscosity varying obtained from experiments are included. The filling process of the micro-channel, which is essential in micro-fluidic devices, is simulated and analyzed. In the result, the effects of surface tension and viscosity on the filling rate of micro injection molding are demonstrated.