射出成型之結構件強度分析與品質改善

Abstract

塑膠件的結構設計分析往往忽略了加工成型所造成的影響，其中包括射出成型過程塑膠溫度分佈不均勻所造成的殘留應力、翹曲變形，另外含有玻璃纖維之塑膠材料在充填時因流動方向的不同而造成不同的纖維排向，都會產生成型品結構強度上的問題。 本論文使用Moldex3D模流分析軟體與ANSYS結構分析軟體，由Moldex3D I2介面輸出模流分析結果，使殘留熱應力、翹曲量和玻纖排向當作結構分析的初始邊界條件，再進行分析與探討，達到模流分析與結構分析的整合，藉此建立連貫式的設計程序，由簡單平板模型來研究成型問題與結構強度的關係，進而衍伸至複雜的幾何結構，如卡扣連接件與機器人腳部零件，達到結構件品質改善目的。 搭配田口實驗方法，找到所希望之最佳參數組合，實驗結果顯示，參數最佳化之射出成型材料可達到結構強度的改良，在機器人腳部零件案例上可改善約37%至57%，能保持所需結構強度又可減輕材料的重量。

本論文以不同於以往單獨使用結構分析軟體的角度設計結構強度，調整射出成型中的加工參數配置，達到結構強度的增加，還可更準確的預測產品結構的破壞及內部應力分佈，使射出成型產品的可靠度與品質有所提升。

The analysis of injection molded parts often ignore the process influence, including the warpage phenomenon and the residual stress caused by the uneven temperature distribution of injection molding. The material that contains glass fibers is causing the structure issue by the dissimilar fiber orientation in the filling. This thesis uses the mold-flow simulation software, Moldex3D, and the structure simulation software, ANSYS. We discussed the residual thermal stress, warpage phenomenon and fiber orientation from Moldex3D I2 interface. Besides, the phenomena of injection molding will be the initial conditions in ANSYS. Integrating mold-flow and structure analysis will establish the coherent design process by researching the relationship between the molding problems and the strength. This study can be extended from a simple flat-panel model to the complex geometries which includes the snap-fit and the part of robot’s feet. We can effectively reduce the required times of experiments with Taguchi Experimental Methods, and find the optimum parameters. According to the result, the material by injection molding of optimum parameters can reach better structure strength, and it can improved about 37 percent to 57 percent on the robot’s feet case. It can maintain the required strength and reduce the weight. This thesis improves the strength by adjusting the process parameters, different from the analysis of using just one finite element software to design, and it also predict the residual stress and the failure of product accurately, to improve the Reliability and the quality.