• Composites Research
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• v.23 no.2
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• pp.31-39
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• 2010

In this paper, composite panels with hat-shaped stiffeners were made using the co-curing, co-bonding and secondary bonding methods. Co-curing is a manufacturing method in which the hat part and the plate are cured simultaneously in a manner that is more cost effective than other methods. Co-bonding is a method in which the stacked prepregs are cured with other cured parts, and secondary bonding is a method in which cured parts are bonded together using an adhesive. A rubber mold was manufactured for co-curing of composite panel with hat-shaped stiffeners, and finite element analyses were done to evaluate the expanding pressure of the rubber mold consistent with the curing temperature. The manufactured panels were also evaluated using a 3-D measurement tester and an ultrasonic tester. Pull-off tests were performed to evaluate their mechanical properties.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.203-206
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• 2008

In this study, we focused on development of the adhesive insulator using the case for solid rocket motors. Material of insulator used unvulcanized rubber based on EPDM/kevlar. In case of front insulator, preforms was made by using hot press molding, and then modified nylon film was inserted between two preforms for boots manufacturing. Rear insulator included cylinder part was embodied by only one mold with special designed and manufactured shape in the process. Boots part of rear insulator was obtained by cutting machine with hard-metal cemented carbide.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.7
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• pp.1533-1538
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• 2003

The present technology of dielectric heating welding for synthetic resin sheet has a switching frequency over 10MHz by using vacuum tube elements, and has restrictively been applied to PVC whose dielectric loss is comparably high. The technology, however, has a difficulty in applying to materials which are made for environment and have low dielectric lose compared with other synthetic resin materials. Recently, the application of materials made for environment is increased so that the technology is faced with the limit. In this paper, a high frequency induction heating welder for synthetic resin sheet is designed applying temperature control by indirect heating to solve the problems about direct heating synthetic resin made for environment.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.141.2-141.2
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• 2016

디스플레이, 센서 등 전자소자는 소형화 단계를 지나 인체 부착형 소자로의 발전을 요구하고 있다. 인체 부착을 위해서는 민감한 피부에 장시간 부착시 무해성과 탈부착의 자유로움이 요구되기에 기존의 화학물질을 활용한 접착 방식에서 개코도마뱀 또는 딱정벌레 발바닥에서 영감을 얻은 자연모사형 건식 접착 방식에 대한 연구가 활발하게 진행되고 있다. 폴리머를 이용하여 자연모사형 마이크로/나노구조 형성은 기계적으로 가공된 금형 몰딩과 후처리를 통한 매우 복잡한 공정이 요구된다. 본 연구에서는 이러한 복잡한 공정을 단순화하기 위해서 폴리머 소재에 플라즈마를 활용한 나노구조를 형성하는 방법을 소개하고자 하며, 건식 접착용 폴리머 소재(PMMA, PDMS)에 따른 표면구조 변화와 표면에너지 변화에 대한 연구를 수행하였다. 플라즈마 표면처리를 위해서 본 연구실에서 자체 개발한 선형이온소스를 활용하였으며 입사에너지, 노출시간, 사용가스에 따른 표면형상 변화를 주사전자현미경을 활용하여 관찰하였다. 또한 처리조건에 따른 표면에너지 변화를 확인하기 위해 물접촉각 변화를 측정하였다. PMMA는 입사에너지, 노출시간이 증가함에 따라 쉽게 나노기둥구조가 형성되었으나, 과도한 입사에너지 또는 노출시간에서는 표면구조가 에칭되면서 무너지는 것이 관찰되었다. 또한 PDMS는 동일한 조건에서 주름구조 형태를 보였으며 노출시간이 증가할수록 주름구조의 간격이 늘어남을 확인하였다. 본 연구 결과를 통해 나노 구조를 쉽게 제어할 수 있는 PMMA가 피부 부착형 접착 패치에 응용이 가능할 것으로 기대된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1045-1050
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• 2011

This study proposed the new pressing method under heat for the plastic automotive interior part in order to make embossing on the skin of the raw material of the part. The raw material is laid on the lower mold and it is pressed by the upper one with embossing shape. The air is suctioned from the inside of both molds for producing tension and making embossing shapes on the skin of the part without its breakage. The corresponding molds and test machines are made and the proposed manufacturing process is validated.

• Composites Research
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• v.26 no.6
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• pp.386-391
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• 2013

In this paper, a carbon fiber/epoxy composite-aluminum hybrid wheel for passenger cars was suggested for better performance and a prototype was fabricated and tested. Adhesive bonding between aluminum part and a composite rim part was used, and the bonding length and thickness were determined by finite element analysis. For self alignment and the function of bonding jig the special structure with a groove and a protrusion was applied. To evaluate the performance of the hybrid wheel various FE analyses were carried out. Inner and outer molds were prepared for the composite rim part and the thermoformed composite part was bonded to the aluminum part. Vibration tests revealed that the hybrid wheel had 16% higher resonance frequency and 32% higher damping capacity with 10% weight reduction.

• Journal of Adhesion and Interface
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• v.17 no.1
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• pp.15-20
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• 2016

Fiber arrangement was important for fiber reinforced thermoplastic composites using injection fabrication. In this work, fiber arrangement in CF/PP was investigated to use electrical resistance (ER) method during injection times. There were 3 types of injection products of CF/PP with different ER change ratio by fiber arrangement. High ER change ratio case of injection CF/PP products had better increased tensile strength. This reason was due to the fiber arrangement of CF/PP by injection. Fractured surface and contact angle of CF/PP products were used to evaluate for injection product quality. Uniform fiber arrangement of CF/PP by injection type exhibited the uniform heat condition of melted CF/PP. Steady thermal transfer effect occurred from melted CF/PP to steel injection mold. Steady thermal transfer effect of CF/PP was transmitted to high ER change ratio of mold. Ultimately, good condition CF/PP product by injection molding method could be predicted by using ER method.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.707-710
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• 2010

The most important things in the KSLV-I Kick Motor nozzle is a development of flexible seal that is utilized to drive a movable nozzle. Especially, a manufacturing technology of flexible seal is one of the key element in the Kick Motor nozzle development. The method used to produce flexible seal in the Kick Motor is injection method. Mold design technology, rubber injection technic and molding process through flexible seal manufacture has been established. After manufacturing, X-Ray inspection have been carried out to confirm a adhesive and internal array of flexible seal.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.82-82
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• 2004

우리나라는 신발 생산 특히 부품소재 부분에서 세계적인 경쟁력을 갖추고 있는 것으로 평가되고 있으며, 이 중 E.V.A midsole은 가볍고 충격흡수성 등과 같은 특성이 매우 우수하여 샌달의 midsole 부품으로 널리 사용되고 있지만 현재의 midsole 제조방식은 생산성의 한계에 직면하고 있다. 즉, 패턴 갑피(upper)와 Phylon mold를 각각 생산한 후 별도의 공정에서 두 제품을 접착하여 샌달을 만들기 때문에 두 제품을 따로 생산하므로 현재와 같은 방식의 제조에 의한 기존 방식의 샌달은 제작비용의 증가 및 생산성 저하 등의 여러 가지 문제점을 가지고 있어 보다 새로운 일체형 자동화 사출 mold에 의한 샌달 제조방식의 필요성이 절실한 실정에 있다.(중략)

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2008.11a
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• pp.94-97
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• 2008

현재 전주 국내에서는 전주에 대한 관심이 조금씩 증가하는 추세지만 그 활용 영역은 많지 않다. 최근들어 휴대폰 관련 부품과 LCD디스플레이의 핵심부품인 도광판 사출금형에 집중되어 있다. 본 연구에서는 반도체 웨이퍼 절단용 블레이드 제작을 목표로 Ni 전주도금층에 조밀하게 $Al_2O_3$를 분산시키는데 목표를 삼았다. 전주(electroforming)를 이용한 Ni-$Al_2O_3$를 첨가한 설파민산 니켈욕에 Surfactant의 양을 조절하며 Sodium Lauryl Sulfate의 첨가량이 많아질수록 Nickel 전주도금층 표면에 $Al_2O_3$는 접착되어지지 않고, 도금층의 두께는 두꺼워졌다. Surfactant의 첨가로인하여 Ni 전주도금층의 표면 장력이 감소하여 $Al_2O_3$를 감싸고 Ni 전주도금층이 성장하여야하는데 교반하는 과정에서 $Al_2O_3$ 입자들이 용액의 흐름에 따라 떨어져 나갔다.