注射成型聚碳酸酯厚度截面的残余应力分析  

Residual Stress Analysis in Cross Section of Injection-molded Polycarbonate

作　　者：郎建林[1] 王韬[1] 葛勇[1] 厉蕾[1] 颜悦[1] 

机构地区：[1]北京航空材料研究院北京市先进运载系统结构透明件工程技术研究中心,北京100095

出　　处：《高分子学报》2017年第6期999-1007,共9页Acta Polymerica Sinica

摘　　要：通过光弹法定量测量了注射成型聚碳酸酯(PC)试样在厚度截面上的残余应力,并结合模具温度的变化与不对称分布,对厚度截面上的残余应力分布进行了详细的研究.结果表明,在厚度截面上,试样边缘分布较高的流动残余应力,芯部分布较高的热残余应力,两区域界面处为流动应力与热应力相互耦合而形成的低应力过渡区;模具温度低于120?C时,PC的残余应力随模具温度的变化并不明显;模具温度高于120?C时,PC的残余应力随模具温度的升高显著降低;不对称模具温度会导致在低模温侧高热残余应力区分布宽,在高模温侧高热残余应力区分布窄.此外,试样的翘曲随模具温度的升高而逐渐增加,不对称模具温度会导致较大的翘曲.The residual stress in cross section of injection-molded polycarbonate（PC） was quantitatively measured by photo-elastic method. The effects of mold temperature on residual stress distribution in cross section and warpage of the whole sample were analyzed in detail. The results show that, in the cross section of the injection-molded PC, the high flow-induced residual stress exists in the skin near the wall of the mold, and the large thermal-introduced residual stress is mainly detected in the core. At the same time, there is a region with low residual stress between the core and the skin in cross section, formed by a mutual coupling of the flow-induced and the thermal-introduced residual stress. The distributions of those residual stresses are influenced by mold temperature. When mold temperature is lower than the heat distortion temperature of PC（126 ？C）,the residual stresses both in the core and the skin are hardly changed with changing mold temperatures. While the mold temperature is higher than the heat distortion temperature of PC, the residual stress decreases significantly with increasing mold temperature. When the mold temperature is at 140 ？C,there are uniform residual stresses in the cross section, and the average retardation measured by photo-elastic method is 230 nm, indicating a low residual stress. Furthermore, the warpage gets worse with increased mold temperature. When the temperatures in the movable and fixed mold are dissymmetry, the shape of the residual stress in the core is trapezoidal. This distribution is caused by uneven cooling. In the movable mold side with high temperature, the region of the thermal residual stress is narrow, and in the fixed mold side with low temperature, the stress is wide. The difference of the thermal residual distribution between the movable and the fixed mold side is more obvious as the mold temperature difference is increased. Finally, the residual stress distribution in a trapezoidal shape leads to a large warpage.

关 键 词：注射成型 聚碳酸酯 厚度截面 残余应力 模具温度 

分 类 号：TQ320.662[化学工程—合成树脂塑料工业] TQ323.41