气体辅助注射成型表层熔体形成机理的分析

基于等温条件下下幂律流体的流动分析，对圆管气体辅助注射成型过程中影响表层熔体形成的因素进行了分析，指出在等温条件下牛顿流体所形成的表层熔体厚度比值约为0．3，接近试验值0．34－0．37，非牛顿流体的值（＜0．3）小于实际气辅成型值（约0．38）。文中对产生这一偏差的非等温条件下的影响因素进行作了进一步的分析，认为除了熔体温度、模具温度以及气体延迟时间对聚合物表层熔体的形成有重要影响，熔体／气体前沿之间的压力梯度值以及熔体／气体界面之间的剪切应力都对气体穿透过程中表层熔体的形成有重要影响。

Mechanism Analysis of the Skin Melt Formation During Gas\|assisted Injection Molding

Factors and relation of skin melt formation under isothermal condition have been analyzed during gas\|assisted injection molding in a tube.This research shows that thickness ratio of skin melt is about 0.3 which is close to the experimental values 0.34～0.37,and that the ratio value (<0.3) of non\|Newtonian fluid is less than the value 0.38 of gas\|assisted injection molding.The difference factors are analyzed under non\|isothermal condition,which shows that shear stress at the gas/melt interface and the pressure gradients existing at the gas and melt fronts are two very important contributing factors forming skin melt thickness in addition to melt temperature,mold temperature and gas delay time,which were recognized as the important influence parameters on the skin melt formation.