Numerical visualization and optimization on the core penetration in multi-cavity co-injection molding with a bifurcation runner structure

doi:10.1007/s00170-017-0330-1

淡江大學機構典藏 > 工學院 > 化學工程與材料工程學系暨研究所 > 期刊論文 > Item 987654321/112932

jsp.display-item.identifier=請使用永久網址來引用或連結此文件: https://tkuir.lib.tku.edu.tw/dspace/handle/987654321/112932

题名:	Numerical visualization and optimization on the core penetration in multi-cavity co-injection molding with a bifurcation runner structure
作者:	Chao-Tsai Huang
关键词:	Co-injection molding;Core penetration;Skin-to-core ratio;Flow imbalance
日期:	2017-04-04
上传时间:	2018-03-13 12:10:23 (UTC+8)
摘要:	Co-Injection Molding and multi-cavity molding are common processes for plastic products manufacturing. These two systems are sometimes combined and applied in the manufacture of bifurcation-structure products. In the previous literature results, the dynamic behavior of the core penetration in co-injection multi-cavity molding with a bifurcation structure is quite complicated and the behavior is sensitive to injection flow rates, different materials, and other process conditions. However, how these influential factors truly affect the core penetration behavior and the detailed mechanism of core penetration behavior has not yet been fully understood. In this study, we focused on studying the multi-cavity co-injection system with a bifurcation runner structure. The results showed that when the skin-to-core ratio is fixed (say 72/28), the melt flow behavior of a co-injection system, utilizing the same material for both skin and core, is very similar to that of a single shot injection molding. Specifically, the non-symmetrical bifurcation runner structure will influence the flow behavior greatly and cause the core distribution imbalance between different cavities. Due to the geometric nature of the bifurcation runner design, this core distribution imbalance problem will still persist even if we modify the melt temperature, mold temperature, or even change the plastic material. Furthermore, when the skin-to-core ratio is fixed (say 72/28), the changes of the flow rate have very little effect on the core penetration result in the final molded product; the final molded product will still have a core distribution imbalance issue. However, we observed that when the flow rate is increased, the core material will occupy more volume space in the upstream portion of the runner and the core penetration distance will be reduced in the flow direction downstream. This feature is very useful to further manipulate the skin-core interface in a multi-cavity system. Moreover, regarding how to improve a poor inter-cavity balance of core material distribution, using a suitable adjustment of the skin-to-core ratio will be greatly helpful. However, the core break-through defect can be a common problem in co-injection molding when an unsuitable skin-to-core ratio is used. To prevent the core break-through defect, increasing the flow rate properly can be one of the good options that we can use. Hence, we concluded that a suitable adjustment of the skin-to-core ratio and a proper flow rate control can be used to optimize the core material distribution in multi-cavity co-injection molding with a bifurcation runner structure. Lastly, in order to validate our inference and the effectiveness of our proposal to improve the inter-cavity imbalance and core break-through problem, a series of experimental studies were performed. And, all experimental results are in good agreement with those of our numerical predictions to further validate the feasibility of our proposed method to gain a better control of the core material distribution with a bifurcation runner structure in multi-cavity co-injection molding.
關聯:	The International Journal of Advanced Manufacturing Technology 92(5-8), p.2545-2557
DOI:	10.1007/s00170-017-0330-1
显示于类别:	[化學工程與材料工程學系暨研究所] 期刊論文

文件中的档案:

档案	描述	大小	格式	浏览次数
index.html		0Kb	HTML	139	检视/开启
Numerical visualization and optimization on the core penetration.pdf		3685Kb	Adobe PDF	37	检视/开启

在機構典藏中所有的数据项都受到原著作权保护.

TAIR相关文章

数据加载中.....