Effect of gas on the polymer temperature in external gas-assisted injection molding

The introduction of gas is the principal difference between external gas-assisted injection molding (EGAIM) and conventional injection molding. In this study, the effects of gas thickness and gas delay time on polymer temperature were discussed. A modified one-dimensional transient heat conduction model of polymer was established to reveal the relationships between polymer temperature and gas thickness and gas delay time in EGAIM. The temperature histories of polymer were obtained by the simulation methods, including Moldflow and ANSYS, and were verified by comparing the experimental data to numerical simulation results. The effects of gas thickness and gas delay time on the temperature histories of polymer will be discussed in detail. The results showed that the polymer temperature is strongly affected by the heat preservation of gas, which in turn, increases with the increase of gas thickness and delay time. This paper provides quantitative methods and theoretical guidance for the study of the effects of gas on the polymer temperature in EGAIM.