應用壓力-溫度-比容(PVT)圖探討成型參數與收縮率關係之研究

Study on the Relation Between Molding Parameters and Shrinkage by Using PVT Diagram

樓映帆(Ying-Fan Lou)

指導教授 ： 陳夏宗

中原大學/工學院/機械工程研究所/碩士(2016年)

https://doi.org/10.6840/cycu201600677

摘要

良好的產品品質之關鍵在於模具設計及參數設定，因此正確的流道設計可使熔膠較為均一的充填至模穴內，而模具溫度、融膠溫度、射出時間、保壓時間、保壓壓力等變數是影響產品品質的重要設定參數。本研究主要目的為應用PVT圖探討成型參數與收縮率之關係。
本研究使用t=2 L/t=100之長平板狀模型進行CAE模流分析及射出成型實驗。材料使用ABS(PA-756)，針對流道設計進行模擬分析，流道設計應使熔膠波前速度一致且壓力降小，利於射出壓力的傳遞。並利用田口法分析得到影響收縮率最大之因子為保壓壓力，其次為模溫。
實驗中，於模內安裝壓力感測器及溫度感測器，參數設定以合理化參數為基準，並以實驗確認參數之正確性，因此本研究由短射實驗得到最佳之充填時間為0.7秒，而實際保壓至澆口凝固時間為5.42秒，非合理化參數之2.42秒。並利用溫度及壓力數據繪製PVT圖探討模溫及保壓壓力對收縮率之關係，較低的模溫，收縮率較小，而此案例中，最佳之模溫為40°C。保壓壓力越大，收縮率越小，但產品厚度會較不均一，此案例中，最佳之保壓壓力為射出壓力之140%。

關鍵字

射出成型 ； 模內壓力 ； 模內溫度 ； PVT ； 收縮率

並列摘要

The key to make the good product quality is mold design that melt can fill into the mold uniform by the correct runner design and the molding parameters have mold temp., melt temp., injection time, packing time, packing pressure, etc. The subject is study on the relation between molding parameters and shrinkage by using PVT diagram.
The strip model t=2 L/t=100 was utilized to the CAE simulation and injection molding experiments. The plastic material was ABS (PA-756). The simulation result shows, the runner design needed to make the velocity of melt front consistent, small pressure drop good for the injection pressure transferring. The largest effect of the shrinkage was the packing pressure, the second was the mold temp. by Taguchi methods.
In the experiment, set up the pressure and temperature sensors in the cavity. Used rationalize forming module to be the standard of the molding parameter that made sure the correctness by the experiment. In the study, the best filling time was 0.7 sec. The real packing time to make the gate frozen was 5.42 sec, not the 2.42 sec by rationalize forming module. Utilize the temperature and pressure data to plot the PVT diagram shows the lower mold temp. and the higer packing pressure can make the shrinkage smaller. However, the higher packing pressure will induce the uneven product thickness. In this case, the best mold temp. was 40°C and the best packing pressure was 140% of the injection pressure.

並列關鍵字

Injection molding ； In-Cavity resin pressure ； In-Cavity resin temperature ； PVT ； Shrinkage

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