薄壁气体辅助注塑件气体穿透过程的研究

基于气体穿透实验技术的研究分析，针对气体辅助注射成形中气体穿透气道的复杂过程，对薄壁气辅注塑件沿圆形截面气道穿透推进并形成模壁表层熔体的充模流动过程进行了研究。通过引入合理的简化和假设，建立了反映充模流动压力梯度、材料性能、表层熔体厚度比、非牛顿指数等影响因素的计算穿透速度和时间的数学方程．对气体注射压力、熔体温度、非牛顿指数影响气体穿透充模过程进行了实例数值模拟研究。结果表明，增大气体注射压力，其气体穿透方向所形成的表层熔体厚度比值也增大，降低熔体注射温度和非牛顿指数会增大气体穿透的壁厚值，其值接近国外试验测定值，也比较符合实际的气辅注射成形工艺结果。

Study on Gas Penetration in Gas-Assisted Injection Molding of Thin Wall Parts

Based on the analysis of gas penetration experiments and aimed at complicated process of gas penetration in gas-assisted injection molding(GAIM), the technology of filling flow in gas penetration along circle channel and forming skin melt on the cavity wall has been developed for GAIM thin wall parts. The mathematic model of solving velocity and time in gas penetration, which are related to cavity flow pressure gradients, material performance, skin-melt thickness ratio and Non-Newtonian index etc., is set up via providing reasonably accurate assumptions, and that the numerical simulation on gas penetration is completed for a GAIM part via changing gas injection pressure, melt temperature, and Non-Newtonian index. Research results show that increasing gas injection pressure, decreasing melt temperature and Non-Newtonian index makes the thickness ratio increase. These results are close to experimental values by foreign investigator and consistent with actual GAIM process.