Postmolding and load‐induced deformation analysis of plastic parts in the injection molding process

Abstract

Abstract To assess warpage and shrinkage of an injection‐molded plastic part, an integrated computer‐aided engineering (CAE) system has been developed. This integrated system employs a simultaneous analysis of the compressible fluid flow, heat transfer, and residual stresses in the polymer during the filling and postfilling stages of the injection molding process and of mold cooling/heating that occurs throughout the entire process. Using the polymer temperature and pressure distributions as a function of time, an analysis has been performed to predict the residual stresses, treating the polymer as a viscoelastic material. The resultant loading is interfaced with the structural analysis program ABAQUS TM to predict the postmolding shape of the plastic part. Analysis has also been performed to evaluate the load‐deflection behavior of a molded part and the effects of different degrees of material anisotropy.