Simulation and verification of the secondary gas penetration in a gas-assisted-injection molded spiral tube

This paper presents both experimental investigation and numerical simulation on the characteristics of the secondary gas penetration in a spiral tube during the gas-assisted injection molding. The primary and the secondary gas penegration phases, corresponding to the filling and the post-filling stages of the molding process, respectively, were identified from the skin thickness distribution along the gas penetration path. Numerical scheme based a dual-filling-parameter technique is first used to simulate the gas front advancement in the primary gas penetration period. Simulation for the secondary gas penetration is developed assuming an isotropic melt-shrinkage model combined with the control-volume/FEM employed on a gapwise layer basis. Simulated result shows good coincidence with the experimental observation.