CAE應用於精密天線蓋之模具設計與研究

CAE Investigation on the Mold Design of Precise Antenna Cover

周強(CHIANG, CHOU)

指導教授 ： 韓麗龍

國立臺北科技大學/機電學院/製造科技研究所/碩士(2010年)

摘要

薄殼件射出成型是目前3C產品最常用的一種成型方式，本研究採用Moldex3D R9.1 CAE軟體，對一模兩穴且不同肉厚(1.1, 1.4 mm)的手機天線蓋進行模擬分析，分析結果作為開發模具的參考依據。研究主題有(1)模流分析：包括澆口(gate)斷面形狀與尺寸、流道的融膠流動路徑、流動平衡、冷卻水路設計，以獲得最小收縮與翹曲之流道設計。(2)模具設計：利用Pro-Engineer軟體進行模具設計，並開發實際模具在射出機台上進行試模。(3)田口方法：使用CAE模流分析軟體作L18(21×37)田口實驗，找出最佳的成型參數。(4)射出塑膠成品：將模具架到射出機台實際射出成品，以研究成型條件對於尺寸位移量的影響。
由模流分析結果得知，最佳澆口型式為圓型斷面，截面積尺寸0.80 mm2；S型流道的流動路徑可以緩衝融膠流動的速度，避免模內壓力迅速增加與剪切應力的產生；流動平衡設計可經由放大澆口截面積尺寸0.80 mm2到0.82 mm2來達成；冷卻水路設計以公模、母模各兩支平行於流道方向為較佳的佈置方式。田口實驗結果可以得知，在95％信心水準以上，影響X軸向位移量最重要因子為保壓壓力，其次為模具溫度；較低的保壓壓力與較高的模具溫度對於X軸位移量值有減小的趨勢，最後由田口實驗分析得到優化成型參數，與實際射出的成品做比較，可以發現兩者位移量趨勢是有差異的，主要是因為射出機的穩定性與精密度，以及量測過程的精度，另外田口實驗採用的水準數過少，這些都會造成模擬與實驗結果之差異。

關鍵字

收縮 ； 翹曲 ； 田口方法 ； 保壓壓力 ； 剪切應力

並列摘要

Thin-shell injection molding has been one of the most widely used molding processes for 3C products today. In this study, Moldex3D R9.1 CAE software was used for analyzing a 2-cavity mold with two different thicknesses (1.1 mm and 1.4 mm) for the mobile phone antenna cover. These analyzing results will be used as the reference data for future mold design. The major fields of my study include four areas of research described in the following. Firstly, on the Mold-flow analysis, the study includes gate type at the cross-section and area sizes, melt-flow paths in the runner, flow balance, and the cooling pipes design. This portion of analyses is to achieve the minimum shrinkage and warpage for runner design. Secondly, on the Mold design, Pro-Engineer Software was used to design the mold, which was then manufactured and tested on an injection machine. Thirdly, on Taguchi method, CAE Mold-flow Analysis Software was used for L18(21×37) for Taguchi method. This experiment is to obtain the optimal injection molding parameters. Lastly, on examination of injection plastic products, the mold was installed on the injection machine to produce the plastic parts. Then, we compiled and studied the injection parameters to find out the factors that show effects on the dimensional displacements.
Results of the mold-flow analysis show that the optimal gate type is found to be circular at the cross-section with an area of 0.80 mm2. S-type runner of flow path can prevent the pressure from increasing rapidly inside the cavity so that it avoids accruing of the shear stress. The design of flowing balance has been achieved by increasing the gate section size from 0.80 mm2 to 0.82 mm2. The cooling pipes were newly designed by inserting two pipes at the cavity side and at the core side. The optimal layout of those two cooling pipes is to align them parallel to the runner’s direction. Our results through Taguchi method analysis with 95％ confidence index indicate that the packing pressure is the most important factor to affect the X-direction displacement, while the mold temperature is placed in second in its overall influence. Lower packing pressure and higher mold temperature tend to favorably reduce the X-direction displacement of Antenna cover. Finally, we have found that some deviations exist in the displacements of the parts between Taguchi experimental analysis values and those of the actual injection molding parts. These discrepancies could be due to the instability of the injection molding machine and the rough accuracy of measuring procedure. Lastly, the level quantities carried out in our experiment might be too few for Taguchi method to achieve high reproducibility. All of the above three factors are believed to have some effects on our final experimental results.

並列關鍵字

shrinkage ； warpage ； Taguchi method ； package pressure ； shear stress

參考文獻

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