應力作用對塑膠射出模具之位移研究

The Action of Stress on Displacement of Plastic Injection Mold

傅家宏(Chia-Hung Fu)

指導教授 ： 韓麗龍

國立臺北科技大學/機電學院/機電整合研究所/碩士(2011年)

摘要

3C塑膠產品的零件尺寸要求越來越嚴謹，除了模具的加工精度之外，模具位移(變形)也會影響塑膠零件的最後尺寸。本研究以模具構造為二板模，成型空間布置為一模兩穴的模具為分析案例。首先利用Moldflow CAE軟體分析射出成形過程之模內壓力分佈及溫度分佈，再將此分析結果載入ANSYS軟體之熱-結構耦合場作為邊界條件。論文研究架構：(a)在射出成型過程中，分別針對結構應力及熱-結構應力對模具所產生的位移作分析；(b)比較不同的模具材料之模內位移及模板位移；(c)應用田口實驗方法與變異數分析，探討射出成型參數對模具位移量的影響，並找出最佳化的製程參數。
研究結果顯示，僅單獨考慮模板結構所造成的結構應力時，其產生的位移非常小且幾乎微不足道；若加入熱結構應力的因素，則產生的位移就會大到不能忽視的程度；因此在實際的模具變形分析必須考慮熱-結構耦合場的情況。由田口方法分析得知，對模具位移影響重要的重要性因子分別為模具溫度、模具間隔塊的距離、模板厚度和模內壓力。比較模具位移量的差異，原始設計為0.062 mm，最佳化後的製程設計所造成之位移量則為0.053 mm，顯示應用田口實驗方法能夠最佳化製程參數組合以及降低模板位移量。

關鍵字

模內壓力分佈 ； 熱-結構耦合場 ； 田口實驗方法 ； 變異數分析

並列摘要

The part dimension of 3C plastic product was required for more and tighter. Either the machining accuracy of the mold or mold displacement (deflection) may be affect on the final dimension of the plastic part. In this study, mold structure is two-plate mold and the molding space layout is two-cavity mold. Moldflow CAE software was used to analyze the in-mold pressure distribution and temperature distribution. And then these analytical data was loaded into ANSYS software as the boundary condition of thermal structure couple field. The configuration of this paper includes: (a) in an injection molding process, analyze the mold displacement under structural stresses and thermal-structure stresses, respectively; (b) comparing the in-mold displacement and mold-plate displacement for the different mold material; (c) using Taguchi experimental method and the analysis of variance, to study the injection molding parameters affect on the mold displacement, and to find the optimal processing parameters.
Results show the displacement of mold is so small that almost can be neglected when the analysis only take into account the structural stresses. However, if the thermal structure stresses was considered, the mold displacement is so enough large and cannot be ignored. Therefore, the thermal structure stresses must be used for analyzing the mold displacement. By using Taguchi experimental method, the significant factors are the mold temperature, mold space block distance, mold-plate thickness, and in-mold pressure. Comparing the difference of mold displacement, the original design is 0.062 mm, and the optimal design is 0.053 mm. This shows the optimal processing parameters and the minimizing the mold displacement can be obtained by using Taguchi experimental method.

並列關鍵字

in-mold pressure distribution ； thermal structure couple field ； Taguchi experimental method ； analysis of variance

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