射出成型模具表面鍍層滯熱方法建置、分析與應用之研究

Investigation on the Establishment, Analysis and Application of Heat Hysteresis via Mold Surface Coating for Injection Molding Process

陳彥成(Yen-Chen Chen)

指導教授 ： 陳夏宗

中原大學/工學院/機械工程研究所/博士(2005年)

https://doi.org/10.6840/cycu200500097

摘要

本研究利用模面鍍層溫度控制方法，在充填階段控制模面溫度介於熔膠溫度及頂出溫度間，於後充填階段模溫快速下降，達到兼顧成型週期與提高品質之目標。
論文中首先分析模面鍍層材料與厚度對溫度場變化及流動分析，評估其滯熱效益，並進行實驗模具的的設計與驗證。第二階段整合紅外線加熱，進一步提昇模具表面溫度，並配合ANSYS熱傳分析並和實驗驗證。第三階段則是探討不同模面鍍層材料與厚度，在不同製程條件下，對拉伸試片的機械性質、表面品質與縫合線的影響。
研究結果顯示，具鍍層的模具可以在充填初始的瞬間，提高熔膠與模面之接觸溫度，且於充填完成後模面溫度迅速下降，形成高溫充填低溫冷卻的特性。在熔膠溫度240℃及模具溫度60℃下，熔膠和鍍層材料為PTFE時之接觸溫度為140.5℃，鍍層材料為TiN時之接觸溫度為83.5℃。而無鍍層P20材料之接觸溫度則只有71℃。當鍍層厚度增加時，接觸溫度的下降趨緩，有助於成形品之充填與保壓階段製程。PTFE鍍層若結合紅外線加熱技術，可讓模面溫度在17秒內，從50℃升溫至120℃。
在成型品質方面，模具表面鍍層滯熱方法對於拉伸強度、光彈性質與縫合線外觀品質均有很大的改善。拉伸強度在PTFE鍍層厚度22μm時，提升23.8%；在PTFE鍍層厚度10μm時，提升19.7%；在TiN鍍層厚度4μm時，提升13.1%。光彈性質與縫合線表面品質，亦有相同的趨勢。整體而言，本研究證實了模面鍍層滯熱方法提供了一個快速而有效的模面溫控，不影響成型週期，並改善成型品質。

關鍵字

模具表面加熱 ； 鍍層 ； 滯熱

並列摘要

The purpose of this research is to establish mold surface temperature control using coating method and aims to achieve high mold surface temperature at filling stage so that plastics product quality can be improved without increasing cycle time.
Influence of different coating materials and thickness on the contact temperature at mold surface and melt flow were analyzed first and the relevant mold design for experimental verification was also designed. Then efficiency of infrared heating combined with mold surface coating was also investigated. Finally, the improvements of tensile strength, weld line mark and residual stress in molded parts due to the present mold surface temperature control were also evaluated.
In summary, heat hyesteresis via mold surface coating using PFTE and TiN provides efficient temperature controlling during melt-filling stage. When melt temperature for ABS is 240℃and mold temperature is 60℃, the contact temperature is 140.5℃for PTFE coating and 83.5℃ for TiN coating whereas for P20 without coating the contact temperature is only 71℃. Integrated with infrared heating, it take 17 second to increase mold surface temperature from 50℃ to 120℃.
For PTFE coating with 22 μm and 10 μm thickness, the tensile strength improvement are 23.8% and 19.7%, respectively. For 4 μm TiN coating, the tensile strength increases by 23.8%. The experiment results also show the same tendency on and residual stress reduction and part cosmetic appearance. In summary, the results show that the mold surface coating provides an effective mold surface temperature control and also improves part qualities significantly.

並列關鍵字

coating ； Heat Hysterssis ； mold surface heaating

參考文獻

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