SIMULATION AND VERIFICATION OF THE SECONDARY GAS PENETRATION IN A GAS-ASSISTED-INJECTION MOLDED SPIRAL TUBE

This paper presents both experimental investigation and numerical simu lation on the characteristics of the secondary gas penetration in a sp iral tube during the gas-assisted injection molding. The primary and t he secondary gas penetration phases, corresponding to the filling and the post-filling stages of the molding process, respectively, were ide ntified from the skin thickness distribution along the gas penetration path. Numerical scheme based a dual-filling-parameter technique is fi rst used to simulate the gas front advancement in the primary gas pene tration period. Simulation for the secondary gas penetration is develo ped assuming an isotropic melt-shrinkage model combined with the contr ol-volume/FEM employed on a gapwise layer basis. Simulated result show s good coincidence with the experimental observation.