結合實驗與數值分析預測射出EVA發泡成型之膨脹形狀

An Experimental Study Coupled With Numerical Analysis For Predicting EVA Foam Expansion Geometry On Injection Molding Process

鄭宜仁(Yi-Ren Jeng)

指導教授 ： 姚宏宗

國立中正大學/工學院/機械工程學系/博士(2012年)

摘要

對於直接射出發泡成型製程來說，準確並且快速的預測縮小模的形狀是一個困難且重要的工作。 而這個製程被廣泛的運用到製鞋工業(球鞋)以產生抗震的鞋子中底。 而根據原始設計的鞋子中底形狀並使用最佳化方法去修改縮小模形狀，則是快速並準確的獲得縮小模形狀的關鍵所在。 本研究對於發泡乙烯-醋酸乙烯共聚物材料(EVA)採用一系列具有不同厚度大小的方塊試片建立起溫度-時間曲線與發泡倍率的關係，並採用熱膨脹方法來模擬發泡放大的過程。 並且採用真實的運動鞋中底來驗證我們模擬正確性，並且發展及應用3D定位與牛頓最佳化方法來獲得縮小模的形狀。 同時最後我們也真實的去製造縮小模並生產球鞋中底成品，並與原來設計的大3D CAD比對，最後結果，其最大誤差皆落在4mm以內，可以符合鞋廠的需求。 故此方法可以大幅的減少鞋廠嘗試錯誤的次數。

關鍵字

類神經 ； 膨脹模擬 ； 熱傳模擬 ； 發泡倍率 ； 有限元素分析

並列摘要

Accurately and rapidly predicting the shrink mold shape of direct injection-expanded foam molding is an important and difficult task. This molding method is widely used by sports shoe sole manufacturers to create shock-resistant materials. Modifying the shrink mold shape using the numerical optimization method is crucial to rapidly obtaining the correct shrink mold size. This study uses a series of rectangle specimens to identify the relationship between the thermal heating of molding and the expansion ratio of ethylene vinyl acetate foam material and then uses this thermal expansion ratio to simulate expansion behavior. The experiments in this study also use the actual shoe sole type, which has the original 3D shape, and use the proposed simulation method to obtain the simulation expansion shape. This study also develops an optimization algorithm based on 3D registration and the Newton-Raphson method to obtain the shrink mold shape. We also manufactured the shrink mold and obtained the shoe sole product to compare any discrepancies between the product and the original 3D shape. The results of this method meet the requirements of the shoe sole factory (i.e., achieve a difference of less than 4 mm). Therefore, this algorithm can reduce the number of iterations.

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