模流分析與射出成型控制參數的優化

Abstract

塑膠射出成型為產業界最主要的製造方法，過去影響塑件射出成型品質的控制參數選定與模具的設計，主要依賴經驗累積與及無數次試誤。本論文探討CAE 模流分析的利用，以模擬及數值解析方式，配合田口實驗設計法去尋求射出成型製程條件與模具設計的優化。從塑膠射出成型件常見的缺陷、分析其成因並尋出對策。對於成型製造過程中的入料、充填、保壓、壓縮、冷卻、脫模各階段□的控制因子及實驗參數如流道設計、塑膠材料、熔膠溫度、充填時間、充填壓力等影響，利用模流分析的方法多維考慮，在品質獲得保證的情況下，以射出成型澆注口壓力最低與產品零件翹曲、變形尺寸最小等，為評估選擇的指標。為增加優化效率，棌用田口實驗設計法規劃控制因子與配置L8(27)直交表來迅速求出製程條件的最優化參數組合。本論文的方法經無線通訊產品的外殼成型實例驗證，可以改進以往師徒經驗傳承及試誤的舊程序，滿足目前日新月異的工業界對產品的品質、速度、精確性的要求。

This thesis applies Computer Aided Engineering (CAE) analysis tool and data analysis methods to simulate the injection molding process, in hope to improve the mold design and modeling process control parameters. The common defects occured on molded plastic products were first examined, and their causes investigated, which lead to the understanding of important factors in the mold design and process parameters for control in order to ensure the product quality. The challenge of this thesis is then on how to find the best values of those design and process parameters. Taguchi experiment design method was adopted to form an L8 (27) orthogonal array of the control factors such as runner design, plastic material, injection time, plastic temperature, tooling temperature, and injection pressure. Injection molding analysis software was then applied to evaluate the plastic flow within the mold to ensure the molding quality. With injection pressure and warpage size of case reduction is (are) the target goal, the best design parameter set was finally determined using Taguchi principles. Using the Access Point Shell, a plastic product for wireless communication as example, this thesis demonstrates that the efficiency of the new method far exceeds the traditional try-and-error process used in current injection molding industry.