射出成形參數逆向求解

Inverse Approach to Determine Injection Parmeters

陳子豪(Zi-Hao Chen)

指導教授 ： 林忠志

國立虎尾科技大學/工程學院/機械與電腦輔助工程系碩士班/碩士(2015年)

摘要

日常生活中塑膠射出製品隨處可見，像是手機外殼、汽車燈罩、及塑膠玩具等，然而進行塑膠射出成形的過程中，為了獲取優良的產品品質，往往必須先設定一組較好的射出成形參數，射出參數眾多且複雜，目前仍仰賴現場的技師及射出工程師使用試誤法和模流分析軟體，找出射出成形過程中較好的參數組合，這兩種方法需依據多次的嘗試錯誤來找到最佳參數組合，既費時且欠缺足夠的資訊來證明模擬參數與製程參數對於產品品質的影響。
本研究使用訊號處理設備，根據模穴內的流變特性找出控制因子(熔膠溫度、射出速度、保壓時間)之成型範圍，再進一步擬定田口直交表對控制因子進行排列組合以減少實驗次數，接著利用迴歸分析建立品質特性(衝擊強度、拉伸負載、重量)與射出參數有關聯的數學模型，最後將數學模型組成矩陣並利用反矩陣及最小平方法的概念對數學模型進行逆向求解。
實驗結果發現以得到的數學模型進行預測值與實際值比較誤差值皆在5%內，變異數分析顯示各方程式的信賴區間都落在95%，聚碳酸酯(PC)的拉伸負載迴歸方程式的信賴區間落在80%，t檢定證實了各項射出參數對聚丙烯材料的產品特性有顯著的影響，聚碳酸酯則較不明顯，3x3矩陣逆向求解，聚丙烯材料實際值與預測值最大誤差30%，聚碳酸酯誤差則相去甚遠，降階逆向求解發現當不顯著因子數量增加時逆向求解的誤差會隨之增加。

關鍵字

逆向求解 ； 流變特性 ； 迴歸分析 ； 田口方法

並列摘要

In this study, the method of formulating the correlation between the molded part quality and the setting parameters in injection process has been proposed. It provides an efficient way to determine a feasible processing window for injection molding process. The correlation matrix which defines the setting parameters and the molded part quality is constructed based on the design of experiment and the validation test to verify the sensitivity of the matrix is also implemented. An inverse approach to determine the setting parameters for a designated performance of the molded part with two plastic materials, polypropylene PP and polycarbonate PC, is presented to show the proposed method has great potential in solving the inverse problem in injection molding process. Comparing to traditional method, this method provides an efficient way to decide the setting parameters of injection process in advance

並列關鍵字

injection molding ； inverse approach ； regression analysis

參考文獻

[1]Yi-qi Wang, Jae-gyu Kim, Jung-il Song，「Optimization of plastic injection molding process parameters for manufacturing a brake booster valve body」，Materials & Design，Volume 56, April 2014, Pages 313–317.

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