B08 应用可视化技术及三维数值模拟对塑料射出成型心型变形之研究

应用可视化技术及三维数值模拟对塑料射出成型心型变形之研究

Application of Flow Visualization Technique and 3D CAE Simulation on the Core Deflection during Plastic Injection Molding

廖惠贞、曾世昌         

Hui-Chen Liao , Shi-Chang Tseng  

国立云林科技大学 机械工程研究所

Dept. of Mechanical Engineering, National Yunlin University of Science & Technology

中文摘要

塑料射出充填过程中，对模具内较高细长比的心型，可以因心型周围充填压力不对称，造成心型产生瞬间甚至永久变形，此现象一般称为心型变形(core deflection) 。Giacomin[1]曾运用无因次化的方法，探讨其对心型变形行为的影响，得到理想状况的一维解析解。其后Yang & Giacomin[2]以Moldex/ANSYS模流应力分析得到二维模拟结果。

本研究设计制作一心型变形可视化实验模具，并进行实际射出实验，以内视镜及高速摄影机观察系统，实时观察拍摄心型在充填模穴过程中的动态变形情形。同时量测心型在成型后之变形量。另一方面，本文利用Moldex3D及ANSYS有限元素仿真软件，来预测心型变形行为，探讨心型周围非对称流动及压力分布，并计算动态心型变形。模拟与实验分析趋势吻合。先前以理论或模拟分析值大于实验值，本文提出应考虑固化层对心型变形并无贡献，于计算压力-面积积分时应扣除固化层面积之影响。

英文摘要

During the plastic injection mold filling process, the pressure field of a high aspect ratio core may become unsymmetric and lead to so-called “core deflection” problem. Giacomin[1] has used method of dimension analysis to obtain 1-D analytical solution of core deflection caused by pressure imbalance. Later Yang & Giacomin [2] have combined Moldex and ANSYS simulations to achieve 2-D core deflection prediction. 

This study aims to set up a real experiment to observe the instant core deflection during mold filling by flow visualization technique. A borescope behind a transparent quartz block was mounted upon a special designed mold cavity to observe the instant core deflection.  The melt front advancement can be captured by a high speed camera as well. The measured deflection data has compared to the simulation result and shown a similar tendency. The measured value is less than the simulated one. This work proposed that the area of frozen layers does not have contribution to the core deflection and can be taken out in the calculation. 

Key words : core deflection, flow visulization, pressure difference, coupled filling/stress simulation.

关键词:

心型变形、可视化、压力不对称、模流应力分析。

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