科盛科技實習技術報告暨塑膠射出成品之凹痕模擬分析與成因探討

The Practical Training Report at CoreTech System (Moldex3D) Co., Ltd. and Study on the Sink Mark of Injected Product and Associated Causes Using Numerical Simulation

陳詩婕(Shi-Jie Chen)

指導教授 ： 黃招財

淡江大學/工學院/化學工程與材料工程學系碩士班/碩士(2022年)

https://doi.org/10.6846/TKU.2022.00110

摘要

本技術報告主要分為兩大部份，首先第一部份為本人在碩士二年級期間，於科盛科技股份有限公司技術訓練部實習一年中，所參與之各項專案與服務，其中包括：案例研究、程式偵錯支援以及技術文件撰寫等相關服務。第二部份，則是在實習過程中科盛公司提供之研究主題作為碩士論文題目的研究探討，而本次的研究內容是針對塑膠射出成品之凹痕模擬分析與成因探索。
隨著現代科技的趨勢，產品逐漸邁向輕薄短小化，為提升產品強度，經常在產品內部增加肋條結構。然而，此等肋條與產品的T型連接區域，卻往往因為肉厚差異或是積熱造成凹痕缺陷影響品質。為此，本研究將應用電腦輔助工程(Computer Aided Engineering, CAE) 探討射出成品中肋條結構造成凹痕缺陷之原因，並應用「進階固態性質收縮 (Solid State Properties of Shrinkage, SPS)」理論，模擬熔膠固化後的應變行為。此外，透過六項成型因子，進行30組預測後，發現保壓壓力是對凹痕最具影響性的操作參數。之後，透過保壓壓力由低至高模擬分析後，可以觀察產品表面T型結構兩側的固化層變化，對應保壓壓力在10-50 MPa即具備一定的抵抗收縮範圍，導致中間凹痕值幾乎不變；而且當有效的保壓壓力越高，抵抗凹痕效果越好。再者，透過在不同保壓壓力與材料溫度及保壓時間之交互作用探討可以發現，當材料溫度越高時只要保壓壓力足夠大，或是在有效的保壓時間內都能有效改善凹痕。另外，針對不同材料種類與凹痕關聯性探討，可以發現材料的pvT特性是影響凹痕量值的關鍵特性，特別是透過CAE模擬分析與實驗進行驗證，結果顯示，不論是採用PP或是PA66 (30%GF)材料，CAE模擬分析預測凹痕量值與實驗量值並不完全吻合，推測是因CAE模擬分析中，目前無法準確計算結晶性材料於室溫後持續收縮的行為，以及射出成品所產生之真空泡現象，此部份可能是目前在凹痕缺陷預測中，CAE模擬分析結果與實驗量值並不完全吻合之主要差異來源。

關鍵字

科盛科技 ； Moldex3D ； CAE模擬分析 ； 射出成型 ； 肋條 ； 凹痕

並列摘要

This technical report is mainly divided into two parts. The first part is to describe that projects and services which I have participated during my second year of master's degree in the Technical Support Department of CoreTech system. It includescase studies, debugging support, and technical documentation writing services. The second part is related to the technical research in the same interternship period. Specifically, the topic for the technical research is “Study on the Sink Mark of Injected Product and Associated Causes Using Numerical Simulation.”
The injection molding process has been applied to manufacture various products for years. However, due to the requirement of high precision for the modern product, the quality requirements of the products are becoming more and more stringent, especially in the thin and light products. To enhance the strength of products, Rib structure desgin is often considered. However, the major reasons to cause these defects are not fully obtained yet. Hence, the objective of this technical research is to find out the main reasons to generate the sink mark defect using CAE simulation. More specific, the new developed “Solid-State Properties of Shrinkage, SPS” function will be considered.
Moreover, to realize what are the major factors to influence the growth of the sink mark, six factors (each one has five levels) has been evaluated. Results show that the packing pressure is the topic key to affect the growth of the sink mark. Specifically, it can be observed that the frozen layers between two sides of T-shape connection area is almost the same when the packing pressure is from 10 to 50 MPa. Those the frozen layers will keep the sink mark deformation around 21.2 m without significant change.
Furthermore, through the interaction study among different packing pressures, material temperature and packing time, it can be found that when the material temperature and the packing pressure are higher enough, packing time can influence the growth of sink mark. In addition, the pvT characteristics of the materials are the key to affect the sink mark changes for different material selection. However, after comparing CAE simulation result and experimental observation for both PP or PA66 (30% GF) materials, the sink mark values are not matched for simulation and experiment. The deviation happened might be due to the prediction capability of the CAE in crystallinity and void formation.
However, the sink mark defects are commonly observed at the T-shape connection area between the ribs and the product. It is expected that due to the heat accumulation around that area.

並列關鍵字

CoreTech System (Moldex3D) Co., Ltd., , ； Moldex3D ； Numerical Simulation ； Sink Mark ； Injection Molding ； Ribs

參考文獻

[1] 科盛科技股份有限公司 (2012), 熔膠管理與控制技術講座. Web Source : https://ch.moldex3d.com/events/past-events/2012meltflipper/

[2] MoldFlow (2021), Sink-mark Prediction Enhancements for 3D Injection Molding Processes, Autodesk, Inc.

[3] 陳夏宗 (2014), 射出成型原理與製程 (Principle and process of injection molding) (初版), 五南圖書出版股份有限公司.

[4] 王茂齡，張榮語，許嘉翔 (2018), 模流分析理論與實務(出版二刷), 科盛科技股份有限公司.

[5] S. J. Liu (2001), Effects of processing parameters on formation of sinkmarks on injection moulded parts, Plastics, Rubber and Composites, Vol. 30, No. 4, pp. 170 - 174.