筆記型電腦螢幕的外部塑膠件是由前框(B件)與背蓋(A件)組合而成,此兩配合件若翹曲過大,裝配後將出現縫隙影響外觀。本研究使用Moldex 3D分析軟體對筆記型電腦螢幕的前框(B件)進行分析,澆口設計為八個進澆點;首先改變澆口直徑,以改善模穴內的流動平衡。然後搭配田口方法(Taguchi method) L8直交表作干擾實驗,找出重要的複合干擾因子,並以L18直交表進行主實驗(main experiments)。其次以變異數分析進行重要因子測試,找出降低翹曲的最佳製程參數組合。最後以確認實驗與信賴區間判定預測值與實驗值是否夠接近。 實驗結果顯示,澆口設計可以使模穴內的流動趨近平衡,並減少翹曲;如果搭配充填時間與料溫的調整,可以進一步改善流動平衡,讓充填結束後的壓力分佈更均勻。影響S/N比的重要因子依序為保壓時間、保壓壓力、料溫、澆口尺寸。由確認實驗得知,在95%信心水準之下,預測值與實驗值是夠接近的,亦即實驗模式是夠精確的。
The external plastic parts of notebook screen is composed by the front bezel and the back cover. If the warpages of these two parts are too large, that will cause poor appearance after assembling. In this study, Moldex3D software was used for analyzing the front bezel of notebook (having eight gates). First, altering the diameter of gate to improve the melt flow balance, then applied Taguchi Method with L8 orthogonal array to find the important compound noise factors, and then applied L18 to execute the main experiments. Secondly, analysis of variance was used to test the important factors and to find the optimal parameter combination for reducing the warpage. Finally, the confirmation experiment and the confidence intervals were applied to assure that whether the predicted value and experiment value is close enough. The results showed that suitable gate design can improve the melt flow balance in the cavity and reduce the warpage. By adjusting the filling time and melt temperature, the pressure distribution in the product will be more even. The significant factors affect the S/N are the packing time, the packing pressure, the melt temperature, and the gate size. Furthermore, the confirmation experiment showed that the predicted value and the experiment value is very close to 95% confident level. That is, the empirical model is as accurate as expected.