• Design & Manufacturing
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• 제8권1호
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• pp.31-34
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• 2014

The Injection molding is used more than 70% of total production in plastic products. The injection molding process has 4 processes such as filling, packing, cooling and ejecting. It spends most of times in the cooling process. Therefore, it is important to control the mold temperature in producing plastic products. The cooling system and time affect the product's quality and productivity. Especially, cooling time has about 60% of total injection cycle time. Therefore, we can improve a productivity by shortening cooling time. In this study, the rapid cooling system was developed and performed a efficiency test. This system could refrigerate coolant to $1^{\circ}C$ and had to need 10 minutes for normal operating. However, if response time of temperature controller and sensor will be increased, the performance of this system will increase.

• 동력기계공학회지
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• 제13권4호
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• pp.38-42
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• 2009

The Injection molding is used more than 70% of total production in plastic products. The injection molding process has 4 processes such as filling, packing, cooling and ejecting. now then, cooling process spends the most of times in Injection molding cycle time. Therefore, it is important to control the mold temperature in producing plastic products. The cooling system and time affect the product's quality and productivity. Especially, cooling time has about 60% of total injection cycle time. Therefore, we can improve a productivity by shortening cooling time. In this study, the rapid cooling system was developed and performed a efficiency test. This system could refrigerate coolant to $1^{\circ}C$ and had to need 10 minutes for normal operating.

• 한국생산제조학회지
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• 제20권5호
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• pp.659-665
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• 2011

Recently, the plastic resin such as PC, ABS are widely used in IT market. Especially, in most cases the keypads mounted on the mobile phone are the dual-injection-plated type. Environmental regulation is based on the quality of injection-molded products and the minimum process steps are required to avoid the plating defects. Various parameters to produce the injection-molded plastic products make it difficult to obtain the desired stability. However, the past experience and the use of CAE analysis make it possible to predict the problems occurred in injection molding process. Especially, the problems of the weld lines such as runner balancing, bending, deformation and forming defects can be solved systematically and minimized by CAE analysis. Through this study, the non-uniform volumetric shrinkage and the difference in temperature distribution induce the deformation and the high value of stress causes the problems such as crack.

• 소성∙가공
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• 제25권2호
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• pp.130-135
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• 2016

Rolled products often have residual stresses or strip waves that are beyond the customer’s tolerance. To resolve this problem, skin-pass rolling is widely used during post-processing of such products. Because a short contact length compared to the strip width is a characteristic of skin-pass rolling, several numerical analyses have been previously conducted based on a two-dimensional approach. In the current study, a series of simulations was conducted using numerical analysis of three-dimensional elastic-plastic finite element method.

• 소성∙가공
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• 제4권4호
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• pp.302-321
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• 1995

A method of determining an optimum blank shape for the non-circular deep drawing process is investigated. The rigid-plastic finite element method is introduced and the computer program code is developed. The ideal shape of a drawn cup with uniform wall height is assumed and metal flow is traced back-ward step by step to predict an initial blank shape of the ideal cup. For examples of the non-circular deep drawing products, three cases of drawn cup with quadrilateral punch shape are considered and optimum blank shapes for each case are proposed and compared with experimental results.

• 한국산업융합학회 논문집
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• 제7권1호
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• pp.69-82
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• 2004

Recently, in the food, paper, steel and plastic industries, plate or sheet type products have been produced by the rolling drum. Steam heating drums are introduced into plastic products facilities in order to keep the density, microstructure, and strength of material uniformly. The drum journal can not help being concentrated by stresses due to the bending and torsion. Especially the drum, heated by high pressure steam, might be exposed in the steam leakage accident. First of all, the stresses on the steam drum journal are to be analyzed, and a case study proper to the subject was performed with a scraped journal, in order to investigate the failure characteristics as well as the initiation and propagation of fatigue cracks, and most probable circumstances of crack initiation. As the result of this study, it is suggested that newly installed drum journal be thoroughly inspected at the next periodic maintenance intervals for evidence of cracking, the microstructure examination and hardness measurements to prevent steam drum from the failure accident.

• 한국금형공학회:학술대회논문집
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• 한국금형공학회 2008년도 하계 학술대회
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• pp.111-114
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• 2008

The Injection molding is used more than 70% of total production in plastic products. The injection molding process has 4 processes such as filling, packing, cooling and ejecting. It spends most of times in the cooling process. Therefore, it is important to control the mold temperature in producing plastic products. The cooling system and time affect the product's quality and productivity. Especially, cooling time has about 60% of total injection cycle time. Therefore, we can improve a productivity by shortening cooling time. In this study, the rapid cooling system was developed and performed a efficiency test. This system could refrigerate coolant to $1^{\circ}C$ and had to need 10 minutes for normal operating. However, if response time of temperature controller and sensor will be increased, the performance of this system will increase.

• 디자인학연구
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• 제19권2호
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• pp.283-292
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• 2006

플라스틱은 19C중반 부족한 자연 재료를 대체하기 위한 물질로 개발되었고, 특히 새롭게 등장한 전기산업 분야에 효율적인 재료로 제공되면서 그 사용성이 확대되었다. 이와 같이 발생 확대된 플라스틱은 제품 디자인 활동과 깊은 연관성을 맺으면서 오늘날 디자인의 주요 재료로 자리하고 있다. 그러나, 플라스틱의 재료적 특성은 디자인 작업과 매우 긴밀하게 연결됨에도 불구하고 재료와 디자인에 대한 면밀한 연구는 거의 볼 수 없다. 본 연구는 플라스틱 재료의 개발이 제품 디자인 활동에 미친 영향에 대해서 고찰함으로써 재료가 미치는 중요성을 밝히기 위함이다. 이를 위해 플라스틱 재료가 개발되어 제품 디자인과 긴밀하게 연결되었던 1920-30년대의 유선형 스타일을 중심으로 고찰하였다. 본 연구를 통해 플라스틱은 제품 디자인 활동과 크게 3가지의 측면에서 깊은 연관성을 맺어 왔음을 알 수 있다. 첫째, 플라스틱의 무형의 재료 특성은 성형 기술과의 긴밀한 관계 속에서 형태화가 가능하며 이러한 특성은 디자인 형태접근에 중요하게 작용하였다. 둘째, 플라스틱은 생산 방식과 재료 특성에서 대량 생산 시스템에 효율적 재료였으며 이러한 특성은 생산비용을 낮추는 경제적인 디자인 방식의 확대를 가져왔다. 셋째, 플라스틱은 다양한 색채와 질감, 광택, 패턴을 만들어 내어 천연 재료의 감각으로부터 인위적인 감각까지 무한히 넓은 변화의 가능성을 가졌으며 따라서 디자인의 다양성의 폭을 넓혔다.

• Journal of the Korean Wood Science and Technology
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• 제45권5호
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• pp.572-579
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• 2017

WPC 내 목질섬유 함량 분석은 신뢰도 높은 목재 플라스틱 복합재(WPC) 소비시장 형성을 위해 상당히 중요하다. 본 연구에서는 polypropylene과 목질섬유를 복합화한 단순 WPC 배합 조건에서 WPC 내 목질섬유 함량에 대한 분석을 TGA를 이용한 열분석 방법과 AMS를 이용한 바이오 탄소 함량 분석 방법을 통해 진행하였다. TGA를 통한 열분해 분석법은 $5^{\circ}C/min$의 승온속도로 고분자 PP의 최대 미분 온도를 이용하여 신뢰도 높은 WPC 내 목질섬유 함량에 관한 검량선을 얻을 수 있었다. TGA와 AMS의 분석 방법 비교에 있어서는, 바이오 탄소 함량을 이용하는 AMS 분석법이 더 높은 신뢰성을 보여주었다.

• Archives of Plastic Surgery
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• 제49권2호
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• pp.158-165
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• 2022

Background Implant-based breast reconstruction has evolved tremendously in the last decades, mainly due to the development of new products and techniques that make the procedure safer and more reliable. The purpose of this study was to compare the outcomes in immediate one-stage breast reconstruction between acellular dermal matrix (ADM) and inferior dermal flap (IDF). Methods We conducted a retrospective comparative study of patients submitted to immediate breast reconstructions with an anatomical implant and ADM or IDF in a single center between 2016 and 2018. Outcomes evaluated included major complications, early complications, reinterventions, readmissions, and reconstruction failure. Simple descriptive statistics and univariate analysis were performed. Results A total of 118 breast reconstructions (85 patients) were included in the analysis. Patients in the IDF group had a higher body mass index (median = 27.0) than patients in the ADM group (median = 24). There were no statistically significant differences among both groups regarding immediate major complication, early complications, readmissions, and reinterventions. Conclusion There are no significant differences in complications between the ADM and IDF approach to immediate implant breast reconstruction. In patients with higher body mass index and large, ptotic breasts, we recommend an immediate implant reconstruction with IDF.