射出成型之排氣設計的分析與驗證

塑膠射出成型的過程中，模穴內原有空氣及成型時之揮發性氣體若無法順利排出，不僅會發生包封、熔接線等缺陷，甚至因模穴無法順利充填導致模穴轉印性不佳等問題，且現行模流分析軟體上無法在完成模具設計後進行準確分析，嵌件與排氣槽等排氣方式均要另行修改網格以利進行模擬，此外設計者的自身觀念不純熟，則會造成各個設計標準不同與相關缺失，造成排氣不良，進而拉長產品的設計週期，連帶著影響其生產成本。因此本研究在射出成型的過程中，改變模具中排氣槽以及排氣間隙的有無，以產品缺陷狀況來確認排氣設計之效果，並且結合CAD軟體與CAE軟體以及網路技術的整合，以二次驗證為最終目的；透過射出壓力、射出殘餘料量等機台反饋數據變化，探討排氣對於製程參數之影響；本研究利用厚薄差異較大之圓平板產品，以掃描、電子天平等測量方式，探討排氣對產品缺陷程度與質量之影響。實驗結果顯示，因排氣機制將模內殘留氣體排出，使射出機殘餘料量隨增加排氣設計而減少，即熔膠射出量增加；因模內氣體殘留而產生之氣體壓力，會增加熔膠流動阻力，隨著排氣間隙之設置，使得熔膠順利充填模穴，同時提生產品重量，降低包封之面積，明顯改善缺陷問題。

關鍵字

二次驗證；排氣

並列摘要

During plastic injection molding process, if the air and the gas from the plastic could not vent properly, there would cause some defects, such as encapsulation and weld lines or even poor transfer because of the cavity was not filled completely. Besides, nowadays mold flow analysis software cannot be carried out the accurate analysis after mold design. Every time inserting venting gap need to modify the grids to simulate. If the designer's own concept is not skillful, it may cause different design and some defects, resulting in poor venting, thereby lengthening the design cycle, even with the impact of their production costs. Therefore, this study controlled the venting gaps in the injection molding process to discuss the venting design by the defects and combined CAD, also the secondary verification as the ultimate goal. To discuss the influence of venting by the data from injection machines, like injection pressure and remain plastics in cavity. This study uses a round and flat product with different thickness to discuss the effect of venting on the product quality by scan, electronic scales and etc. methods. Experimental results show that the venting mechanism makes the gas exhausted from the cavity to make residual quantity decreases, which means increases the amount of melt shot. Since the gas pressure within the mold because of the residual gas would increase the melt plastic flow resistance. With the venting gap, the melt could smoothly fill the cavity. Thus this study increases raw product weight, reduces encapsulation, and improves defects.

並列關鍵字

Secondary verification, Venting design

參考文獻

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射出成型之排氣設計的分析與驗證

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