Abstract: Based on the power law model，a transient，pure viscous，non-isothermal theoretical model of water-assisted co-injection molding was developed, and finite volume method was adopted to simulate the filling stage of water-assisted co-injection molding process. The influence of these factors, such as inner-outer injection volume, inner-outer rheological index ratio, water injection temperature, water injection velocity, water injection delay time, inner melt temperature and mold temperature on the fluids filling patterns of water-assisted co-injection molding process were investigated. And the simulation results were explained theoretically based on rheological theory.

Key words: water-assisted co-injection molding;filling process, numerical simulation