• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.1335-1336
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• 2010

• 대한기계학회논문집A
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• 제28권6호
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• pp.826-837
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• 2004

Rotational molding is a plastics processing technique that is ideally suited to producing relatively large, hollow, seamless parts which are partially or totally enclosed. Designers of plastic parts turn to rotational molding to produce small or large parts of unusual shape that cannot be produced as one piece by other processes, e.g., blow molding and thermoforming. In this paper, in order to enhance the quality of rotational molding plastic products, 1) surface features for the plastic products are characterized by using an image analysis system, 2) maximum tensile strength for the plastic products that are made of materials that consist of Samsung-Atofina R90lU, pigments and two different kinds of calcium carbonate (OMYA CaCO$_3$) is measured and compared with each other by using an Instron universal testing machine, 3) thickness for the plastic products is non-destructively measured to investigate the quality of the plastic products by using an A-scan ultrasonic tester.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2003년도 학술대회지
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• pp.341-347
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• 2003

Single flighted screw extrusion is the most cost effective method for the production of film, sheet, pipe and the fundamental step in other processes including blow molding and injection molding The temperature and injection pressure in barrel play a very important role in quality of products. Because thermal distortion and displacement of barrel by temperature difference and injection pressure difference cause irregular resine melting and flow. In this paper thermal distortion and stress of barrel includes pressure and temperature distributions by finite element analysis to understand dynamic characteristics of barrel.

• 한국정밀공학회지
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• 제17권7호
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• pp.124-131
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• 2000

Rapid Prototyping(RP) models are no longer used only for design verification. Currently, parts built utilizing layer manufacturing technology can be employed as functional prototypes and as patterns or tools for different manufacturing processes such as vacuum casting, investment casting, injection molding, precise casting and sand casting. This trend of Rapid Prototyping application meets the requirement of concurrent engineering and its range covers a more spreaded area. The aim of this paper is saving the manufacturing lead time and cost of plastic parts having hollow space shapes used by prototype-car. Using rapid prototype patterns, made by the Selective Laser Sintering(SLS) technique, a new approach of manufacturing resin-based blow mold is discussed. It has a great potential fur making prototype-car parts with the batch size of under 200 parts, in case of rapid modification due to a subsequent design changes in developing stage. So, the process proposed in this research shows reduction of process time and manufacturing cost when compared with the conventional process such as a Zinc Alloy fur Stamping(ZAS) mold.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 동계학술발표대회 논문집
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• pp.66-66
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• 2006

• 한국기계가공학회지
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• 제16권6호
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• pp.63-68
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• 2017

The purpose of this study is to improve the whitening phenomenon around the PET preform gate for blow molding. CAE analysis of plastic injection molding has been applied to design of preform shape and select the injection molding conditions. A ceramic insulation gate with lower thermal conductivity than metal is applied to improve the whitening phenomenon created around the gate in the injection molding process. According to the results of CAE analysis, the warpage deformation at the square corner was estimated to be about 0.34 mm at the bottom. From the results of the temperature history analysis, it was confirmed that the resin near the gate cooled more rapidly than the cavity. Ceramic insulated gates were fabricated to reduce the cooling rate and experiments were conducted to confirm the effectiveness of the whitening phenomenon improvement. As a result of the ceramic insulation gate experiment, it was confirmed that the whitening phenomenon was significantly reduced around the gate.

• 폴리머
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• 제35권5호
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• pp.467-471
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• 2011

PET병은 프리폼(preform)을 사출성형한 후 이를 블로우 성형기에 이송시켜 블로잉하여 성형된다. 내열을 요구하는 병 즉, 주스나 곡류음료용 PET병은 목 부분(neck 또는 thread 부분)에 내열성을 부여하기 위해 프리폼 성형 후 블로잉하기 전에 목 부분을 결정화시킨다. 그러나 사출성형품에 존재하는 잔류응력이 결정화를 방해하기 때문에 프리폼 목 부분의 충분한 결정화를 위해 사출 후 프리폼을 열처리(annealing)한다. 이 열처리는 잔류응력을 해소시키기 위해서 수행하는데 사출 시 성형조건의 최적화를 통하여 잔류응력을 최소화한다면 열처리 시간을 단축시킬 수 있다. 본 논문에서는 사출 시 프리폼에 형성되는 잔류응력을 최소화하고 치수정밀도를 유지하기 위한 연구로 CAE 해석을 통하여 최적 사출조건을 제시하였다. 성형조건별 잔류응력 및 수축률의 변화를 관찰하고 이를 최소화시키는 성형조건을 찾기 위해 실험계획법을 적용하였다. 사출온도, 보압크기, 그리고 사출시간을 인자로 하여 최적의 성형조건을 결정하였다. 잔류응력에 영향을 주는 인자는 사출온도와 사출시간 순으로 나타났고 수축률에 영향을 주는 인자는 사출온도로 나타났다. 본 연구에서 결정한 최적 조건에서 최대 잔류응력, 잔류응력의 분포, 그리고 수축률이 기존 조건에 비해 각각 22%, 40%, 그리고 25% 감소하였다.

• Archives of Plastic Surgery
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• 제38권1호
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• pp.35-42
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• 2011

Purpose: Blow-out fractures can be reduced using various methods. The orbital reconstruction technique using a balloon under endoscopic control has advantages over other methods. However, this method has some problems too, such as postoperative follow-up, management of the balloon catheter, and reduction of the posterior orbital floor. Thus, we developed a simple, effective method for orbital floor reduction that involves molding and shaping the antral balloon catheter. Methods: A 0, 30, or $70^{\circ}$, 4-mm endoscope was placed though a two-point, 5-mm maxillary antrostomy. The balloon catheter is placed directly at the orbital apex to reconstruct the anterior shelf (spherical shape), while it is turned in a U-shape towards the anterior maxilla for the posterior shelf (elliptical shape). Orbital floor defects, compound or comminuted fractures are reconstructed with alloplastic materials through an open lid incision under the endoscopic control. Results: This technique was applied to ten patients with orbital floor fractures: five anterior shelf and five posterior shelf fracture, respectively. Four of the patients had zygomatico-orbital fractures, while the rest had isolated orbital floor fractures. Two patients were given porous polyethylene implants Synpor$^{(R)}$) and three underwent reconstruction with a resorbable mesh plate. No complication associated with this technique was identified. Conclusion: The freestyle placement and selection of a urinary balloon catheter under endoscopic control and the preoperative estimation of the volume enhanced the stabilization of the orbital contour. This method improves the adaptation of the orbital floor without the risk of injuring the surrounding orbital contents, dissecting blindly, or using sharp traction. One drawback of this method is the patient's discomfort from the catheter during treatment.

• 한국산학기술학회논문지
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• 제16권10호
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• pp.6655-6665
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• 2015

할로겐계 난연제의 환경적 문제로 인한 규제가 강화되면서 비할로겐타입의 인계화합물을 기초로 한 난연제의 비중이 높아지고 있으며, 기능성 film 제조에 있어 난연 효과를 보이는 적인 첨가에 따라 수지의 물성 및 열적 특성이 확연히 달라진다. 난연 효과를 높이고자 난연제 과량 첨가시 수지의 물성은 크게 저하되며, 수축 또는 방청 등 기능성 film에 적용되기 어렵다. 본 연구에서는 적인MB의 함유량에 따른 LDPE film을 blow 타입의 사출공청을 통해 제조하였고, 이에 대한 난연성 시험과 인열 강도 및 수축률, 방청성 평가를 통해 적인-LDPE film의 기계적 특성 및 물성특성에 미치는 영향력과 함유량에 따른 적인난연 film의 특성연구를 그 목적으로 하였다. 난연성의 경우 VTM 0를 보였으며, 인열 강도의 경우 MD 및 TD의 경향성이 상반되는 것을 알 수 있었다. 수축률의 경우 함유량에 따른 특성은 보이지 않았으며, 방청성의 경우 국내 방청 수축 필름 신뢰성 규격의 기준인 0.05 % 보다 우수한 결과를 보였다.

• 한국포장학회지
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• 제22권3호
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• pp.103-106
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• 2016

태국의 플라스틱 소비는 포장분야 49%, 직물 15%, 건설 11%, 전기전자가 10% 순으로 나타났다. 종사자는 106천명이며 공장생산 용량대비 실제 생산은 85%이고 식품포장용 플라스틱수지 수요는 월간 135천톤에 달한다. 업종별 제조사는 필름가공업체가 503개 공장으로 전체의 39%를 점하며 인젝션 몰딩 사가 231개로 18%, 블로우 몰딩 사가 216개사로 17% 순으로 나타났다. 주요 수지들의 생산은 PP는 총 1,950천톤을 생산하였으며, LDPE는 685천톤을 LLDPE는 1,150천톤을 생산하였고, HDPE는 1,920천톤을 생산한 것으로 나타났다. 플라스틱 수입은 16,668백만 바트였고 수출은 33,778백만 바트로 수출액이 2배 이상 높은 것으로 나타났다.