动态保压注塑成型的动态数值仿真与实验结果分析  

Dynamic Numerical Simulation and Experiment Results of Oscillating Packing Injection Molding

作　　者：杨浩 周伟辰 高雪芹[1] 雷军[1] 李忠明[1] Hao Yang;Wei-chen Zhou;Xue-qin Gao;Jun Lei;Zhong-ming Li(College of Polymer Science and Engineering,Sichuan University,Chengdu 610065)

机构地区：[1]四川大学高分子科学与工程学院

出　　处：《高分子学报》2019年第12期1348-1356,共9页Acta Polymerica Sinica

基　　金：国家重点研发计划(项目号2018YFB0704202);四川省科技计划项目(项目号2018G20332)资助

摘　　要：为实现动态保压注塑成型(OPIM)的智能精密制造,以哑铃型拉伸试样构建几何模型,以Dynamic feed系统还原保压阶段中复杂的动态流动场,运用Moldflow模拟仿真出OPIM全过程.通过与传统注塑成型(CIM)的对比研究,探究了OPIM在保压阶段的熔体流动情况、皮芯结构上熔体温度以及剪切速率分布与大小的变化.通过二维广角X射线衍射(2D-WAXD)、扫描电子显微镜(SEM)以及显微镜实验对模拟结果进行验证.结果表明,在OPIM过程中,熔体在较低黏度下可反复通过型腔,在型腔厚度方向上产生温度梯度,形成强剪切场,进而诱导分子链伸直,形成串晶结构,从而提高了OPIM制品性能,模拟与实验结果一致.To realize the intelligent precision manufacturing of oscillating packing injection molding(OPIM),the whole process of OPIM was creatively simulated by computer-aided technology, Moldflow. In the process of simulation, the model was built as a dumbbell-shaped tensile spline and the complex dynamic fluctuating flow field caused by reciprocating piston motion in packing stage was initially emulated by the Dynamic feed system.According to complex changes of temperature, pressure and extra shear field, cross WLF model were selected as the constitutive laws for HDPE in this study. The melt flow distribution, variation of the melt temperature and shear field in sample were investigated in OPIM simulation, meanwhile the results were also compared with those of conventional injection molding(CIM) simulation. The results show that, in the OPIM process, HDPE melts could repeatedly pass through the cavity at lower viscosity by the strong reciprocating motion of pistons, creating the temperature gradient at the thickness direction and forming a strong shear field, thus inducing the molecular chains to straighten and further form the shish-kebab structures. Finally, The real morphology and structure of OPIM and CIM samples were characterized by 2 D-WAXDSEM. The results show a higher orientation and more shish-kebab structure in OPIM compared with those in CIM. Melt flow traces observed by microscopy confirmed the multiple melt flow under the action of pistons in cavity. The simulation results are in good agreement with our experiment results. Finally, this article provide the theoretical OPIM process window for high-performance sample processing and new simulation ideas for special injection moldings additional external force field.

关 键 词：动态保压注塑成型(OPIM) Dynamic feed 皮芯结构 剪切分布 保压阶段模拟 

分 类 号：TQ320.662[化学工程—合成树脂塑料工业]