Analysis of thermal residual stress in plastic injection molding

The characteristics of plastic injection molding were considered using the theory of thermo-viscoelasticity by considering the effect of packing bulk strain during the cooling stage of the injection molding process. The mathematical model governing the development of residual stress in the amorphous polymer has been established. The residual stress model is solved with the finite difference method. Due to the rapid changes at the initial stage, a quasi-numerical procedure is adopted for evaluating the integral terms arising from the thermal residual stress model during the cooling stage. The results are discussed with an illustrative example.