NUMERICAL MODELING OF THE MOLD FILLING STAGE IN GAS-ASSISTED INJECTION-MOLDING

This paper presents an effective numerical model capable of simulating the filling stage of the gas-assisted injection molding process, part icularly the gas penetration phenomenon involving the gas-polymer inte raction. A Galerkin Finite Element model is used to model the polymer flow during the filling and gas penetration stages. The polymer flow f ront and the gas-polymer interface are tracked using a volume tracking technique. Finally, a finite difference technique has been used to ca lculate the temperature across the thickness. Comparison between numer ical simulation predictions and the experimental data for a plate moul d as well as for a complex part is presented.