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Numerical Investigation of Warpage in Insert Injection- Molded Lightweight Hybrid Products
Trieu Khoa Nguyen,이봉기,황철진 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.2
In this study, a numerical investigation of warpage found within insert injection-molded frame parts was carried out based on the Taguchi method in conjunction with a response surface methodology. An integrated mold frame unit was recently developed by integrating a conventional mold frame, metal reflector, and bezel together, to be used in a back light unit system of a liquid crystal display. Such an integrated plastic-metal hybrid part could be successfully manufactured through the insert injection molding process. However, minimization or even elimination of warpage, one of the severe defects found in injection-molded products, is required for reliable mass production. Therefore, a numerical analysis was performed to reveal the effects of the relevant processing parameters, showing that packing pressure played the most significant role, originated from temperature difference between corners of the final product. Furthermore, a double optimization process combining the Taguchi method and the response surface methodology was employed to determine accurate and optimal processing conditions. The results clearly verified that the current combination technique can overcome the Taguchi method’s limitation, resulted from a discrete optimization nature, and also effectively give more accurate optimum solutions without complicated algorithms and software.
Nguyen, Trieu Khoa,Lee, Dong-Weon,Lee, Bong-Kee Institute of Pure and Applied Physics 2017 Japanese Journal of Applied Physics Vol. No.
<P>In this study, a numerical investigation of microcantilever sensors for detecting the contractile behavior of cardiomyocytes (CMs) was performed. Recently, a novel surface-patterned perforated SU-8 microcantilever sensor has been developed for the preliminary screening of cardiac toxicity. From the contractile motion of the CMs cultured on the microcantilever surface, a macroscopic bending of the microcantilever was obtained, which is considered to reflect a physiological change. As a continuation of the previous research, a novel numerical method based on a surface traction model was proposed and verified to further understand the bending behavior of the microcantilevers. Effects of various factors, including surface traction magnitude, focal area of CMs, and stiffness of microcantilever, on the bending displacement were investigated. From static and transient analyses, the focal area was found to be the most crucial factor. In addition, the current result can provide a design guideline for various micromechanical devices based on the same principle. (C) 2017 The Japan Society of Applied Physics</P>
측벽 및 홀 구조를 포함하는 바이오 부품의 플라스틱 사출성형 기술 개발
Trieu Khoa Nguyen,차경제(Kyoung Je Cha),이봉기(Bong-Kee Lee) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11
In the present study, a plastic injection molding technology was investigated for a mass-replication of the biomedical product with complicated features. The current plastic biomedical product, which is one part of the novel biomedical device, was designed to have a cylindrical sidewall and rectangular hole. Because the complicated features like sidewall and hole can lead to the critical defects, such as weldline formation, air trap, short shot, and breakage, during the injection molding process, both the precise design of the injection mold and optimization of the processing parameters are required. In this regard, the injection mold to produce the biomedical product with sidewall and hole structures was designed and manufactured. The experimental and numerical investigations of the injection molding filling stage were carried out. From the investigations, the detailed filling sequence and flow behavior were identified, thereby verifying the feasibility of the current mold design.