粉末共注射成形充模流动过程前沿位置及场分布的数值模拟

Numerical simulation of melt front and filed profile in powder co-injection molding filling process

对粉末共注射充模流动过程进行数值分析和实验验证。采用实验和数值拟合的方法确定芯/壳层界面的厚度,并运用改进的控制体积法对芯、壳层喂料前沿进行追踪。采用有限元和有限差分法对控制方程组进行数值求解,用Matlab进行程序开发,获得芯、壳层充模过程中的熔体前沿分布以及温度场和压力场的分布情况。将模拟结果与实验结果进行对比分析,发现在充填初期,模拟的喂料前沿位置与实验较为吻合,但随着充填的进行,两者偏差增大,其原因可能是在模拟过程中没有考虑注射坯的收缩。

The powder co-injection molding filling process was analyzed and verified by the theory of numerical analysis and experiments. The thickness of core/shell interface was determined by experiments and numerical fitting. The melt front was traced by a modified control volume. The pressure equation and energy equation were solved by hybrid finite element/finite difference approaches. The simulation program was developed by means of Matlab, as a result the tracking of movement of skin front and core/skin interface and profile of temperature and pressure fields were obtained. Finally, simulation results were compared with the experimental ones. The simulated results agree well with the movement of feed＇s forefront. With the filling of the feed, the deviation between simulation results and the test results increases. The reason may be that the contraction of injected parts is ignored in the process of numerical simulation.