滑鼠底座之最佳化設計與製程研究

Optimized design and Molding–Process study of Mouse Base

陳廣文(Guang-Wen Chen)

指導教授 ： 韓麗龍

國立臺北科技大學/機電學院/精密機構設計產業研發碩士專班/碩士(2007年)

https://doi.org/10.6841/NTUT.2007.00359

摘要

現有電子、資訊產品零件的成形方法幾乎都以塑膠薄殼射出為主，因此預防薄殼成品翹曲變形益顯重要。本研究針對平整度要求甚高(小於0.04 mm)的滑鼠底座為實驗對象，探討製程條件與機構設計對滑鼠底部翹曲變形之影響。首先利用模流分析軟體Moldex 3D模擬滑鼠底座的充填、溫度、壓力的分佈狀況，以及成形所產生的翹曲量。其次配合田口方法的實驗設計，找出製程參數與成形品質的關係，減少實驗次數及提高品質。控制因子為七因子、三水準，包括模具溫度、融膠溫度、保壓壓力、保壓時間、冷卻時間、射出壓力與射出速度等。而干擾因子則是保壓壓力：一因子、二水準，以L18(21×37)直交表探討製程條件之最佳化組合。根據信號雜訊比(signal to noise ratio, S/N)的比值輔以變異數分析(ANOVA)，深入探討射出成形參數對翹曲變形影響的程度。實驗結果顯示，保壓壓力對翹曲變形的影響最大，且由最小翹曲量的分析得到了最佳化製程參數。接著再以此最佳化的製程參數來模擬滑鼠底部增加肋結構後對翹曲變化的影響，此肋結構是作為靜電放電牆(ESD wall)防護而設計。結果發現增加肋結構之後，對於滑鼠底部的翹曲量並無明顯改善，但一定的肋高與肋厚可以產生補強的作用。最後探討滑鼠光學孔的偏移量對翹曲變化的影響，分析結果顯示，光學孔偏離滑鼠底座中央位置越遠，則翹曲量越大。

關鍵字

翹曲變形 ； 田口方法 ； 直交表 ； 信號雜訊比 ； 變異數分析 ； 靜電放電牆

並列摘要

Nowadays the parts of electronic and information products are almost manufactured by the plastic thin-shell injection molding. It is very important to prevent the warpage of the plastic thin-shell parts. This study examines the injection process conditions and mechanism design versus the warpage of bottom of the mouse base that require smaller than 0.04 mm. First, the mold-flow software Moldex 3D is used to analyze the filling, temperature, and pressure distribution and the amounts of warpage. Next, the experimental design of Taguchi method is introduced to study the relationship between injection parameters and quality controls. This is to reduce the percentage of bad and increase the quality. The numbers of control factor are seven which include mold temperature, melt-plastic temperature, packing pressure, packing time, cooling time, injection time, and injection velocity. And the numbers of level in each factor is three. In addition, packing pressure is used as noise factor, which includes one factor and two levels. Therefore, an orthogonal arrays L18(21×37) will be analyzed in this experimental design. The warpage of bottom of mouse versus the injection parameters then can be obtained by the value of signal to noise ratio (S/N) and analysis of variance (ANOVA). Results show the packing pressure is the critical factor that affects the warpage of mouse bottom. Besides, optimized injection parameters with the smallest warpage also can be obtained in this study. Third, a pair of ribs is designed that can work as the protection of electro-static discharge wall (ESD wall). These ribs are analyzed the effect of warpage under the optimized injection parameters which were found previously. Results show the rib design can not improved the amount of warpage. However, the rib can enhance the strength of mouse. Last, we examine the deviating distance of optics hole of mouse that will affect the warpage. Results indicate that the larger the deviating distance is, the larger the warpage will be.

並列關鍵字

warpage ； Taguchi method ； orthogonal arrays ； signal to noise ratio ； analysis of variance ； electro-static discharge wall

參考文獻

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