氣體輔助加熱應用於射出成型高深寬比微結構之研究

Study on the Gas-Assisted Heating Technology Using in High Aspect Ratio Micro-Structure Parts of Injection molding

游士諄(Shih-Chen Yu)

指導教授 ： 陳夏宗

中原大學/工學院/機械工程研究所/碩士(2010年)

https://doi.org/10.6840/cycu201000680

摘要

在射出成型製程中，動態模溫控制技術將能夠同時兼具高模溫與短週期的條件，可以在充填前給予短暫的高模溫，使熔膠在模穴內有更好的流動性，將可提升微結構產品的轉寫性及改善傳統射出時所面臨的表面品質問題。其中，氣體輔助加熱也是屬於動態模溫控制的一種。
本研究中，首先對氣體輔助加熱參數影響性做探討，同時使用CFD模擬分析軟體建立完整3D模型來進行模擬與實驗驗證比對，之後透過模擬結果來探討微結構內的溫度分佈與氣體流場分佈；接著比較模溫控制機加熱與氣體輔助加熱的加熱冷卻效率，最後將此製程實際應用於高深寬比微結構射出成型上，探討此製程對高深寬比微結構的成型轉寫高度。
研究結果顯示，加熱氣道間距大小對於加熱的均勻性影響較大，而氣體流量快慢則是影響到加熱速度；所以，加熱氣道間距為8 mm時加熱均勻性佳，氣體流量在400 l/min加熱後的溫度越高，且表面的溫度分佈實驗結果與模擬分析結果比較後趨勢一致；當氣體加熱在未搭配滯熱層及熱阻隔層的情況下對模具表面進行加熱，其加熱深度僅0.04 mm，因此，加熱及熱散都會非常的快速。使用模溫控制機將模具從70oC加熱至100oC需要610秒；而使用氣體加熱僅需20秒，可明顯得知氣體加熱的優勢。在高深寬比微結構成型實驗結果得知，隨著加熱目標溫度的提高，可有效提升微結構成型轉寫高度，且成型的微結構深寬比可達12，同時也證明此製程的可行性。

關鍵字

氣體加熱 ； 動態模溫控制 ； 高深寬比微結構射出成型

並列摘要

In the injection molding process, Dynamic Mold Temperature Control technology will be capable of achieving both high temperature and short cycle time for a given molding condition. This technology enables pre-fill mold heating for better melt flow which strengthens the micro-structure of the product. In addition, surface quality issues are eliminated and the replication accuracy is increased. The type of Dynamic Mold Temperature Control used in this study is gas-assisted heating.
The first step in this study is to observe the effect of changing parameters on temperature distribution. The experimental results are then compared to the 3D simulation model using CFD software. This software is also used to simulate gas flow within the system. After comparing the heating and cooling efficiency of gas-assisted and mold temperature control heating, this proved that gas-assisted heating is more efficient. This process is then applied to high aspect ratio micro-structure injection molding and the replication accuracy observed.
The results of this study show the gap between the mold cavity and core has an impact on the pre-fill mold heating uniformity. The gas flow speed affects the heating rate as well. Heating uniformity was found to be greatest when the gas channel spacing was set at 8mm and a gas flow rate of 400 l/min had the most efficient heating. The experimental results were then compared to the simulation and analysis. When observing gas-assisted heating without a high thermal diffusivity layer (Ni) and low thermal diffusivity layer (ZrO2), the mold surface heating depth was only 0.04mm. Thus, the heating and cooling rate of the mold is rapid. Temperatures from 70oC to 100oC take 610 seconds using the mold temperature control whereas gas-assisted heating merely takes 20 seconds. The results show that the gas-assisted heating method is suitable to conventional mold temperature control methods. In high aspect ratio experiments, the replication accuracy of product micro-structures increased with the temperature of the mold surface. Our experiments reached a maximum aspect ratio of twelve which demonstrates the effectiveness of the gas-assisted heating method for mold temperature control.

並列關鍵字

Dynamic mold temperature ； High Aspect Ratio ； Gas heating

參考文獻

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