射出成型模具表面瞬間加熱建置與分析之研究

INVESTIGATION ON THE ESTABLISHMENT AND ANALYSES OF INSTANTANEOUS MOLD SURFACE HEATING IN INJECTION MOLDING

彭信舒(Hsin-Shu Peng)

指導教授 ： 陳夏宗

中原大學/工學院/機械工程研究所/博士(2003年)

https://doi.org/10.6840/cycu200300522

摘要

含加熱系統之高模溫的應用，解決了大部份傳統射出成型品的問題，特別是薄殼、微小/微特徵射出成型品對於高壓、超高速機台的需要性、模具特殊要求和高強度塑料流動性的考慮大幅降低，顯示出高模溫的重要性。高溫模具的應用雖然成功解決產品成型上的問題，但也因此增加了模具冷卻時間。因此，本研究之目的在建置一套模具瞬間加熱系統以及建立電腦輔助工程瞬間加熱模擬技術，利用感應加熱系統搭配冷卻液進行模具表面瞬間加熱與冷卻溫控實驗、模擬以及效益評估，以達到同時兼顧縮短成型週期與高生產量率之目標。
論文中，首先對ANSYS應用於含加熱源模具溫度場分析與驗證做一討論，以確定ANSYS軟體在分析含加熱源模具溫度場之可行性。其次，則對電磁感應磁熱耦合分析理論做一確定。第三階段進行感應加熱能源供應系統建立、感應線圈設計以及建立模具溫度量測/資料擷取系統。第四階段則對ANSYS電磁-熱耦合分析應用於感應線圈設計進行分析，以進行感應加熱實驗尋找相關操作參數並驗證分析可信度。最後，進行實例分析包括感應加熱模板(含冷卻水路)模具溫控實驗以及含電熱管/冷卻水路之加熱模板模具溫控實驗，對模板瞬間加熱溫控實例分析、驗證與效益評估做整合性探討。
研究結果顯示，ANSYS模擬含水路設計模板瞬間加熱溫控模擬分析結果與實驗分析趨勢相當接近，成功建立感應加熱3D磁-熱耦合模擬分析技術，有效預測模板加熱所需要的加熱時間與操作條件。從案例分析一(符合手機尺寸含冷卻水路設計之模板(110mm×110mm×35mm))結果得知，從110℃升溫至200℃使用電熱管加熱需要37秒鐘，消耗功率64.75kW；使用感應加熱僅需4秒鐘，消耗功率40kW。模板從200℃降溫至110℃使用電熱管加熱之模板需要冷卻30秒；使用感應加熱之模板需要21秒鐘。從案例分析二結果得知，加厚之模板從40℃升溫至240℃使用電熱管加熱需要174秒鐘，消耗功率304.5kW；使用感應加熱僅需3.47秒鐘，消耗功率61.25kW。模板從240℃降溫至40℃使用電熱管製程需冷卻251秒；使用感應加熱製程僅需要60秒鐘。結果顯示，模板厚度增加且加熱升溫的溫度值愈大時，感應加熱更能凸顯出瞬間加熱的效率，本研究已充分說明感應加熱提供了一個快速而有效的模面加溫技術，同時對於成型週期不會有太大的影響。

關鍵字

磁-熱耦合分析 ； 渦電流 ； 瞬間加熱 ； 感應加熱

並列摘要

High mold temperature provided great contributions to conventional and advanced injection molded parts. Especially, it can decrease the requirement of high-performance machine, special mold and high flow resin for thin-wall or micro/micro-feature molding processes. Nevertheless, high mold temperature also increases cooling time of injection molding cycle. Hence, the purpose of this research is to establish instantaneous mold heating system and set up 3D magnetic-thermal coupled-field analysis technique. To evaluate the benefits of instantaneous mold surface heating in reducing molding cycle and enhance productivity of plastics products with multidisciplinary function under rapid-delivery industrial request.

In this study, the first stage will discuss the simulation feasibility of mold temperature field analyses with heating apparatus by ANSYS software. The next, the capability and accuracy of simulations on the induction heating were verified via experiments. The third stage will establish induction heating system, coil design method and infrared thermal image captured technology. The fourth stage will implement CAE analysis and experiment to find out correlative operation parameters of induction heating and optimum coil design for induction heating experiments. Finally, induction heating and electric heat pipe heating experiments on a flat steel mold plate with cooling channel design will be executed. Mold surface temperature distribution during induction heating and electric heat pipe heating process was measured using infrared thermal image system. The experiment results were also compared with simulation results.

In summary, for case I, a flat steel mold plate of 220 mm by 220 mm by 35 mm is used for the experiments. To evaluate the practical purpose of induction heating and heat pipe on the real injection molding, a mold plate, roughly about an inset size of cellular phone housing, designed with four cooling channel design and running 12℃ coolant were utilized for the demo experiment. Mold surface temperature increases from 110℃ to 200℃. It takes 40kW power and 4 seconds for induction heating, 64.75kW power and 37 seconds for electric heat pipe heating. It takes another 21 seconds for mold surface to cool down to 110℃ by induction heating method, 30 seconds by electric heat pipe heating method. For case II, a flat steel mold plate of 220 mm by 220 mm by 42.5 mm is also utilized. Mold surface temperature increases from 40℃ to 240℃. It takes 61.25kW power and 3.47 seconds for induction heating, 304.5kW power and 174 seconds for electric heat pipe heating. It takes another 60 seconds for mold surface to cool down to 110℃ by induction heating method, 251 seconds by electric heat pipe heating method. The results show that rapid heating and cooling of mold surface temperatures using induction technology was successfully illustrated.

並列關鍵字

Instantaneous heating ； Eddy current ； Induction heating ； Magnetic-thermal coupled analysis

參考文獻

1.A. I. Isayev, Injection and Compression Molding Fundamentals, Marcel Dekker Inc., New York (1989).

2.H. H. Chiang, Simulation and Verification of Filling and Post-filling Stages of the Injection-Molding Process, CIMP Tech. Report, No.62, Cornell Uni., Ithaca (1989).

6.Donggang Yao, Ming Chen and Byung Kim, Development of Rapid Heating and Cooling Mold Inserts Comprising A Heating Layer An Insulation and Substrate, SPE ANTEC Tech. Paper, pp.704~708 (2001).

7.Donggang Yao and Byung Kim, Development of Rapid Heating and Cooling System for Injection Molding Applications, Polymer Engineering and Science, Vol.42, No.12, pp.2471~2481 (2001).

11.李育芸, 感應加熱應用於模具表面快速加熱之研究, 私立中原大學機械工程研究所碩士論文(2002).