基于CAE分析的轿车外角撑装饰板双料重叠注射成型质量控制

发布时间：2018-02-23 06:21

  本文关键词： 外角撑装饰板 双料重叠注射 制件翘曲 界面结合强度 浇口位置组合 工艺参数优化　出处：《西华大学》2011年硕士论文　论文类型：学位论文

【摘要】：双料重叠注射作为一种“模内组装”或“模内焊装”成型技术,具有减少或取消二次装配、缩短制件成型周期等诸多优点。但由于设备、模具、成型工艺等因素的制约,使得双料重叠注射技术的大规模应用受到一定限制。因此,加强相关研究和开发显得尤为重要。 轿车外角撑装饰板通常位于轿车后侧窗玻璃拐角处,由主体结构和边缘密封两部分组成。该制件在双料重叠注射成型中所面临的典型质量问题是翘曲量偏大和界面结合力欠佳。为解决此类质量问题,传统的做法往往是依靠实践经验反复调试模具或注射参数来寻求最佳质量控制的途径。毫无疑问,这将导致生产成本的上升和能源的浪费。利用注射成型CAE技术不但可以预测外角撑装饰板成型过程中原先只有通过试模才能暴露的成型缺陷,而且还可借助数值实验结果,优化双料重叠注射工艺方案,提高成型产品质量,同时降低生产成本。 本文在排除某外角撑装饰板结构工艺设计不合理和前后注射材料匹配不当等因素的基础上,借助Moldflow软件,重点研究双料重叠注射浇口位置组合与注射工艺参数对制件翘曲和界面结合的影响。 为此,本文首先拟定四种浇口位置组合方案,通过对这四种方案的实验结果对比分析,找出成型外角撑制件的最佳浇口位置组合;然后基于最佳浇口位置组合安排正交试验,研究前、后注射材料的熔体温度、注射时间、保压压力、冷却时间及模具温度等工艺参数与制件翘曲和界面结合的关系;最后综合成型质量、设备吨位、成型周期等因素,选取最佳工艺方案并加以验证。本文的研究结果表明: 1.浇口位置组合对外角撑装饰板最终成型质量影响较大。其中,成型制件密封边上的浇口位置不同会影响后注射组份的熔体剪切速率和模腔内的压力分布,进而影响流动路径上的熔体温度分布和熔体密度分布。不均匀的温度分布和密度分布会造成制件密封边上不同区域的收缩不均,当由此引发的残余应力大于重叠注射材料的屈服强度时,密封边便产生翘曲。此外,不均匀的熔体温度分布还会影响后注射组份向与之接触的基体表面传热,进而影响基体侧的局部熔化深度及熔化持续时间,最终影响基于界面分子相互穿插渗透的界面结合力。 2.不同的工艺参数对制件翘曲和界面结合两个指标的影响程度不同。在给定的参数取值范围内,先注射材料(ASA)的冷却时间对两个指标的影响均很弱;而重叠注射材料(TPV)的注射时间对两个指标的影响却均较强;ASA保压压力对制件高度方向的翘曲影响较大,对界面结合力的影响却属中等;而TPV注射温度对界面结合强度的影响非常显著,但对制件翘曲影响却较小。 3.在ASA熔体温度255℃、注射时间1.0s、保压压力取最大注射压力的70%、冷却时间15s和TPV熔体温度200℃、注射时间0.7s、保压压力取最大注射压力的70%、冷却时间25s以及模具温度70℃条件下成型外角撑装饰板,其总体和高度方向的翘曲量均有不同程度的降低,且界面结合力也能得到较大改善。
[Abstract]:As a kind of " in - mold assembly " or " mold - in - mold welding " molding technology , double - material overlapping injection has many advantages such as reducing or eliminating secondary assembly , shortening the forming period of products , etc . However , the large - scale application of double - material overlapping injection technology is limited due to the factors such as equipment , mold , forming process and so on . Therefore , it is very important to strengthen the relevant research and development . in ord to solve that problem of quality control , the traditional practice often rely on the practice experience to repeatedly debug the mold or injection parameters to seek the best quality control . On the basis of eliminating the factors such as unreasonable design of the structural process of an outer corner brace and improper matching between the front and back injection materials , this paper focuses on the influence of the double - material overlapping injection gate position combination and the injection process parameters on the warpage and the interface of the product by Moldflow software . In this paper , four kinds of gate position combination schemes are proposed firstly , and the optimum gate position combination of the molded outer corner brace is found by comparing the experimental results of these four schemes . Then , the optimum technological scheme is selected and verified based on the optimum gate position combination . Finally , the optimum technological scheme is selected and verified by the factors such as temperature of melt , injection time , pressure maintaining pressure , cooling time and mould temperature . The results show that : in addition , that uneven temperature distribution and the density distribution can cause the contraction of different areas on the seal edge of the article to be nonuniform , and when the residual stress caused by the uneven temperature is larger than the yield strength of the overlapping injection material , the seal edge can cause warpage . 2 . The influence of different technological parameters on the warp and the interface of the products is different . The influence of the cooling time of the first injection material ( ASA ) on the two indexes is very weak in the range of the given parameter . The influence of the pressure of the ASA on the height direction of the product is relatively strong . The influence of the pressure of the ASA on the interfacial bonding strength is moderate ; however , the influence of the TPV injection temperature on the interface bonding strength is very significant , but the influence of the TPV injection temperature on the interfacial bonding strength is small . 3 . At the ASA melt temperature 255 鈩，

本文编号：1526335