水辅助注塑制品残余壁厚影响因素仿真分析

残余壁厚是衡量水辅助成型制品质量的重要指标，研究工艺参数对残余壁厚的影响规律对生产工艺具有重要指导意义。基于流体体积法，应用计算流体力学（CFD）计算软件分析了工艺参数对水辅助注塑三维弯管残余壁厚的影响。仿真分析中为了完整描述熔体黏度在实际成型中的变化，利用软件中的用户定义功能（UDF）完成对熔体黏度模型的定义。模拟分析表明：注水速率与熔体注射量是影响水管件成型质量的主要因素。提高注水速率，使得短时间内有更多熔体被推向前方，形成更小的残余壁厚。提高熔体注射量会降低水体穿透空间，得到的水管件残余壁厚更大。另一方面，本次模拟分析中诸如注水温度、模具温度、熔体温度等因素对残余壁厚影响并不大。

Numerical analysis of process parameters influencing residual wall thickness in water-assisted injection molding

Residual wall thickness is an important indictor of evaluating water-assisted injection molding products.Research on the influence of process parameters on residual wall presents important references for production technology.Based on volume of fluid method,numerical simulations are conducted to detect the influence of processing variables on residual wall thickness of water pipe.Viscosity model of melt is defined by UDF to precisely describe changing behavior of melt viscosity.The simulation result suggests that the water injection velocity and short shot size and turn out to be the principal parameters which affect the residual wall thickness.This is due to the fact that improvement on water injection rate leads to much more melt pushed forward in a short time.Residual wall thickness decreases accordingly.Increasing the volume of short shot size causes much less space left for water to penetrate,consequently,residual wall becomes much thicker.In addition,other processing variables such as water temperature,molding temperature and melt temperature have little effect on residual wall thickness.