外部氣體輔助射出成型對補強肋成品表面品質之研究

Study on the Part Surface Quality of Rib with External Gas-Assisted Injection Molding

陳夏宗(Shia-Chung Chen) ； 蘇建嘉(Chien-Chia Su) ； 林明俊(Ming-Chung Lin)

《南亞學報》 31期 (2011/12) Pp. 175-186

https://doi.org/10.6989/JN.201112.0175

摘要

在本研究中，利用長100mm、寬50mm、以及厚度1.5mm的平板，搭配四種與平板厚度不同比例之肋的設計（分別為0.6、0.8、1與1.2倍），並採用一般拋光表面與鏡面拋光8000表面等兩種不同表面成型方式，以及以ABS塑料為成型材料，來探討外部氣體輔助射出成型各製程參數對產品表面收縮凹痕深度之影響。然後再根據前項實驗結果，設計一組外部氣體輔助射出成型最佳化製程參數並與傳統射出成型製程做一比較，藉以分析比較外部氣體輔助射出成型對產品表面收縮凹痕深度品質改善之最大效益。研究結果顯示，製程參數中以模具溫度、氣體壓力及氣體保壓時間為影響產品品質的三個關鍵參數。模具溫度影響熔膠充填入模穴後凝固層的厚薄，進而影響氣體保壓的效果，因此影響最大；其中產品表面品質會隨著模具溫度升高而提升，但效果會趨於緩和；產品表面收縮凹痕深度會隨著氣體壓力增加而降低，且達到一極限值；氣體保壓時間亦有類似氣體壓力之影響。而在肋厚較大之區域則需要較大的氣體壓力及較長之氣體保壓時間將熔膠不斷的推擠向模面，以獲得較佳的產品表面品質。

關鍵字

肋 ； 收縮凹痕 ； 凝固層

並列摘要

In this study, a plate part (with dimensions of L100mm×W50mm×T1.5mm) associated with different ratio (0.6, 0.8, 1.0 and 1.2) of rib height to plate thickness were designed to conduct the experiments. ABS resin and two different shaping surface including surface polishing and 8000 mirror polishing, respectively, were External Gas-Assisted Injection Molding to investigate the effects of processing parameters on the surface shrinkage depth of molded parts. Meanwhile, according to the result of the experiments, we developed the optimal processing parameter for External Gas-Assisted Injection Molding and to compare with the Traditional Injection Molded parts in order to observe the best benefit of improving products' appearance. From the measured results, it was found that the mold temperature, gas pressure, and gas packing time are the three key parameters affecting products' shrinkage depth. Among them the surface quality of the products was improved as the temperature of the mould raised, but the result tended towards the stability. The surface shrinkage depth of molded parts decreased with the gas pressure and reached limited values. Gas packing time shows similar influence on the surface shrinking depth of molded parts as the gas pressure. Mold temperature is the primary key parameter because higher mold temperature resulting in thinner freeze layer that can help to raise the effect of gas packing. The thicker width of rib area needs the higher gas pressure and the longer gas packing time to push melt forward to the surface continually to acquire better quality.

並列關鍵字

rib ； sink mark ； freeze layer