塑膠件凸轂設計對鎖附扭矩之研究

Boss Design of Plastic Part Affect on Locking Torque

陳京凡(Ching-Fan Chen)

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

凸轂(boss)於塑膠產品中利用自攻螺絲作為組裝、定位、限制、支撐等用途。若凸轂強度不足，在螺絲鎖附時會產生成滑牙。本實驗中，凸轂固定孔徑尺寸(1.6 mm)，三種不同的外徑3.2, 4.0和4.8 mm，(亦即肉厚0.8, 1.2和1.6 mm)，搭配四種不同數量的補強肋(0, 1, 2及 4)。兩種塑膠材料：ABS及PC，成形參數調整四種不同的保壓大小(0%, 15%, 30%及45%)，成形完成之試片再以自攻螺絲及扭矩試驗機測量boss承受的最大鎖附扭矩，Tmax。結果顯示PC材料之凸轂承受的Tmax較ABS為大。在boss設計時增加肉厚與補強肋數目可以提高Tmax；射出成形參數方面，增加保壓壓力也會提升凸轂的Tmax。其中以增加凸轂肉厚，對於提升凸轂的最大鎖附扭矩影響最為顯著。

關鍵字

凸轂 ； 補強肋 ； 鎖附扭矩 ； 保壓壓力

並列摘要

In plastic parts, boss was combined with self-tapping screw that can be used for assembly, supporting, positioning, and restricting process. Boss strength must be large enough to against the locking torque. In this study, boss was designed with the same inside diameter of 1.6 mm, three types of outside diameter 3.2, 4.0 and 4.8 mm, (i.e. three types thickness of 0.8, 1.2, and 1.6 mm), and four types of different ribs (rib numbers equal 0, 1, 2, and 4). Two types of plastic material are the PC and ABS. Injection molding parameters contain four packing pressure including 0%, 15%, 30%, and 45%. Molded specimens were tested by use of self-tapping screw and torque tester for measuring the maximum locking torque, Tmax. Results show the Tmax of boss on PC is greater than those of on ABS. Increasing the boss thickness and rib number will enhance the Tmax. In the processing parameters, the larger the packing pressure is, the higher Tmax obtained. Finally, we find the boss thickness is the most notable factor for the maximum locking torque, Tmax.

並列關鍵字

boss ； strengthening rib ； locking torque ； packing pressure

參考文獻

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