宗瑋工業公司實習技術報告與應用異型水路設計提升射出成型模具效益之研究

Technical report of practical training at Grand Dynasty Industrial Co., Ltd. and Study on the conformal cooling channel design to improve the mold efficiency

陳宣瑋(Xuan-Wei Chen)

指導教授 ： 林國賡

共同指導教授 ： 黃招財(Chao-Tsai Huang)

淡江大學/工學院/化學工程與材料工程學系碩士班/碩士(2020年)

https://doi.org/10.6846/TKU.2020.00704

摘要

本技術報告主要分為兩大部分，第一部分為本人於學校研究共射成型製程的成果；第二部分為本人於宗瑋工業股份有限公司進行實務實習的成果及心得，在實習期間，主要工作為新產品開發過程中可能遭遇之缺陷問題，並加以解決，另外，在實習過程中也將產品遇到的問題進行深入探討，進行具有學術研究之異型水路對於成型效益影響專案。
隨著科技的進步，人們對於塑膠產品的需求量越來越多，產品尺寸精度與外觀要求也越來越精密，然而產品大量製造的同時，相對也造成環境上的衝擊，又因目前是個分秒必爭的時代，如何降低射出成型週期與提升產品外觀，同時又達到節能減碳，已成為工業界的目標之一。因此本研究第一部分為共射成型中纖維配向的動態變化與其對產品品質影響之研究，希望透過共射成型(co-injection)之技術，達成產品大量製造後，塑料回收再利用，減少能源的耗損，我們透過模擬分析(Moldex3D)與實驗研究方法，以標準拉伸試片(ASTM D638 TYPE V)為系統，探討共射製程中內部纖維排向與機理的影響。研究結果顯示，透過基本共射充填分析，皮/芯層比例為60/40時具有良好之芯層滲透分佈，亦即皮層材料可以完整包住芯層材料；接著我們利用Moldex3D同時針對單射及共射系統進行纖維動態變化探討時發現，當固定在試片節點量測時，單射纖維排向與共射纖維排向差異不大，但共射系統有較低的纖維排向。另外，為進一步確認此等現象，我們也進行實驗試模驗證。首先進行共射芯層滲透變化行為確認；接著進行拉伸試驗發現利用共射製程之試片因具有較差之排向，導致拉伸強度下降約4%。第二部分為應用異型水路設計提升射出成型模具效益之研究，希望應用異型水路模具能提升產品生產率以及良率，降低產品製程週期與節能減碳。影響射出成型週期最主要的因素為產品之冷卻時間，主要原因為產品之冷卻時間約佔據了整個射出成型週期的70%，然而傳統射出成型之模具，因加工方式簡單，以一般的鑽孔方式加工而成的直進直出的冷卻水路，無法有效帶走熔膠熱能，若生產幾何形狀更加複雜的產品，傳統水路更是無法有效控制產品的冷卻機制，為了突破傳統模具上的限制，宗瑋工業股份有限公司引進金屬3D列印機，製作異型水路(conformal cooling channel)模具，然而異型水路的設計如何能使射出成型模具發揮最大的效益，至今仍是一項挑戰，為此本研究以CAE數值模擬分析與實際試模實驗，探討傳統水路與異型水路之間的差異以及不同異型水路設計下的差異。結果顯示，傳統水路因無法進入產品內部進行冷卻，導致產品有積熱區域產生，造成冷卻時間增加，與模具溫度差異過大，而使用異型水路可以降低10%的冷卻時間，也進一步提升產品品質；接著，我們也探討不同異型水路設計對產品的影響，我們比較3組異型水路設計發現，異型水路能越接近產品輪廓設計以及冷卻水路產生較大之紊流，產品的翹曲變形越小，產品所需冷卻時間也減少。

關鍵字

宗瑋工業 ； 射出成型 ； CAE模擬分析 ； 異型水路 ； 金屬3D列印

並列摘要

This technical report is mainly divided into two parts, the first part is the research results on the co-injection molding process during my first year of Master program at Tamkang University; the second part is the report of the practical training experience at GDI. During the internship, the main work to solve the defects that encountered during the development of new products in injection molding.
The demand for plastic products is increasing day by day, it drives the dimensional accuracy and appearance requirements of products becoming higher and higher. However, at the same time as much more production of products has been sent into the market, they also cause environmental impacts. How to reduce the injection molding cycle and improve product quality, while achieving energy saving and carbon reduction, has become one of the goals of the industry. Hence, the first part of this study is“Dynamic Variation of the Fiber Orientation and Its Influence on the Product Quality in Co-injection Molding”. It is expected that the co-injection technology can be used to handle the recycled plastics. In this study, we have applied both CAE simulation (utilized Moldex3D) and experimental study to investigate the core-layer penetration behavior and the fiber orientation variation dynamically on the single-shot and co-injection molding based on the standard tensile bar (ASTM D638 TYPE V) system. Results shows that through the basic co-injection filling analysis, the skin/core layer ratio is 60/40 can provide suitable core-layer penetration without blow-through numerically and experimentally. When fixed at the point A of the standard tensile bar, the single-shot fiber orientation is not much different from the co-injection molding, but the o-injection molding system has a lower fiber orientation. In order to further confirm these phenomena, we also performed a tensile testing for the single-shot and co-injection molding specimens. Results show that the co-injection molding specimens exhibit a lower tensile stress by 4% due to the lower fiber orientation in flow direction. The second part in this thesis is“Study on the conformal cooling channel design to improve the mold efficiency”. It is expected that the conformal cooling channel design can improve product productivity and enhance yield rates of the molds. In general, the most important factor to affect the injection molding cycle is the cooling time. However, in the traditional injection molding mold design, the cooling channel is made using the general drilling method. It can only made the straight-in and straight-out cooling water channel and that kind channel cannot take away the heat energy of the melt effectively. If a product with more complicated geometry, the traditional cooling channel cannot effectively control the cooling effect of the product. In order to solve the limitations of traditional molds, GDI constructed metal 3D printer machine and technology to make conformal cooling channel molds. However, even having the great 3D printer machine how the design of conformal cooling channels can maximize the benefits of injection molding molds is still a challenge. In this study, we have applied both CAE simulation (utilized Moldex3D) and experimental study to investigate the differences between traditional cooling channel design and conformal cooling channel design. Specifically, several different conformal cooling channel designs have been discussed. The results show that the traditional cooling channel cannot be installed into the inner of the moldbase, and resulting in increased cooling time and excessive temperature difference from the mold. On the other hand, using the conformal cooling channel design can reduce the cooling time by 10% and further improve product quality significantly. Moreover, we also discuss the influence on the product quality by utilizing different conformal cooling channel designs. Specifically, based on the comparison for three different conformal cooling channel designs we found that the one which can make the conformal cooling channel closet to the mold surface and the one which can provide the largest turbulent flow of the cooling channel could be the great designs.

並列關鍵字

GDI ； Injection molding ； CAE simulation analysis ； Conformal cooling channel ； Metal 3D printer

參考文獻

[1] 宗瑋工業股份有限公司http://www.grand888.com/.

[2] A. B. Strong. (2005). Plastics: Materials and Processing (3rd Edition) (pp. 687-695).

[3] P. J. Garner, & D. F. Oxley. (1971). British Patent 1,156,217.

[4] R. Seldén. (2000). Co‐injection molding: Effect of processing on material distribution and mechanical properties of a sandwich molded plate. Polymer Engineering & Science, 40(5), 1165-1176.

[5] W. M. Yang, & H. Yokoi. (2003). Visual analysis of the flow behavior of core material in a fork portion of plastic sandwich injection molding. Polymer testing, 22(1), 37-43.