• 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 Vacuum Society Conference
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• 2012.02a
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• pp.480-481
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• 2012

LED (Light Emitting Diode)는 친환경적이며 고수명 등의 여러 장점을 가지고 있어서 액정디스플레이의 광원으로 널리 사용되고 있다. 그러나 LED 제품을 제조하기 위해서는 칩, 패키지, 모듈, 시스템으로 구성된 4단계의 복잡한 제조공정을 거쳐야 하므로 가격이 높은 단점이 있다. 이를 개선하기 위해서 패키지, 모듈, 시스템의 3단계의 공정을 하나로 통합한 hybrid LED package(HLP) 개념이 제시되었다. HLP는 LED chip을 PCB에 직접 실장한 뒤 초정밀 가공 및 성형 기술을 활용하여 일체형 광학패턴을 인가함으로써 공정을 단순화하면서도 광효율을 향상시킬 수 있다. 이에 본 연구에서는 다구찌 실험계획법을 사용하여 디스플레이에서 중요시되는 휘도를 높일 수 있는 일체형광학패턴 형상 최적화를 실시하였으며, 최적화된 일체형 광학패턴을 제조하기 위한 초정밀 가공 및 성형기술을 개발하였다. 최적화 결과 높이 25um, 꼭지각 90도의 음각형태의 사각피라미드 패턴이 최적형상으로 결정되었으며, 패턴이 없을 때와 비교하여 휘도가 약 32.3% 높아지는 것으로 나타났다. 이러한 일체형 광학패턴을 제품으로 구현하기 위하여 초정밀 절삭기술을 활용하여 마스터 금형을 제작하였다. 최종적으로 사출성형을 통해 일체형 광학패턴을 제작하게 되는데 이때 사출기 내부 공기흐름 및 진공도를 최적화함으로써 패턴 내부에 불필요한 기포가 발생하지 않도록 하는데 성공하였다. 이를 통해 생산성이 높은 사출성형으로 HLP 제품을 양산할 수 있는 가능성을 확인하였고, 추후에는 실제 제품을 제작하는 연구를 수행할 예정이다.

• Journal of Welding and Joining
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• v.22 no.3
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• pp.14-17
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• 2004

일체화 성형 기술은 복잡한 형상 또는 여러 개의 부품으로 구성된 제품을 1회의 가공이나 축약된 수의 부품을 이용하여 최종 형상으로 생산할 수 있는 기술로서 생산 공정의 단축, 재료비의 절감, 자원 및 에너지의 절감 등과 함께 경량화를 꾀할 수 있는 차세대 성형기술이다.(중략)

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.2
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• pp.127-133
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• 2013

In this paper, the study for the manufacture of the integrated composite wing is performed. The wing has a pivoting structure and high aspect ratio to increase lift drag ratio. The wing is designed with carbon fiber composite because the wing needs to be light and have sufficient strength and stiffness to satisfy structural design requirements. The number of structural members is decreased by part integration to reduce manufacturing cost and the wing is manufactured with the integrated molding process by an autoclave. The material properties are identified by the coupon tests and the structural strength and stiffness are verified through the component tests.

• Journal of the Korea Convergence Society
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• v.8 no.12
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• pp.275-281
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• 2017

The automobile cowl cross bar which is a backbone frame part inside the cockpit module has been designed with more complex geometries recently due to demands of its enhanced functions and reduced weight of car. The traditional manufacturing process using welding between tubes with different diameters shows several problems such as poor mechanical characteristics and appearance, etc. Therefore, in this study, manufacturing processes which can eliminate the welding process were developed by applying one-piece metal forming processes such as tube drawing and radial swaging. As results, it was found that the one-piece manufacturing processes give better bending strength than the traditional welding process and the swaging process shows the lowest manufacturing cost.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.8
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• pp.751-758
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• 2009

Failure strengths of composite single-lap adhesive joints were investigated with various parameters such as manufacturing method, overlap length and adherend thickness. A total of 335 single-lap joint specimens were tested under tension. Specimens were fabricated with 4 different manufacturing processes; cocuring without and with adhesive, secondary bonding and co-bonding. Each manufacturing process has 5 different overlap lengths and 4 different thicknesses, respectively. As expected, failure strength is higher in thicker adherend joints and lower in larger overlap length specimens. Interesting result is that the secondary bonded joints show the higher strength than the cobonded and cocured joints with adhesive, and give close or even higher strength compared with non-adhesive cocured case.

• 기계와재료
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• v.15 no.2 s.56
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• pp.59-66
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• 2003

• Journal of Welding and Joining
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• v.15 no.2
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• pp.54-63
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• 1997

For the purpose of establishing laser welding condition (laser power, welding speed and beam focus) and of evaluating tailored blanks for two kinds of thin steel sheets SPCC and SK5M using in the thin plate structure such as automobile, train, and so on, investigated their $CO^2$ laser weldability under various initial welding conditions. SPCC thin sheet showed good weldability under some welding conditions. But, high carbon steel sheet SK5M needed heat treatment after welding to obtain ductility of the welded joint. And next, tailored blank was tested through deep drawing to evaluate reliability of their obtained laser welding conditions. The forming depths by tailored blank were SPCC+SPCC=22-25mm and SK5M+SK5M=13-25mm.

• The Science & Technology
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• v.32 no.3 s.358
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• pp.63-67
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• 1999

새로운 기술 LIM은 공압출과 사출성형을 일체화한 기술로 비교적 복잡한 라멜라(층상)모폴로지(형태학)를 갖는 블렌드제품을 생산하는 방법이다. 종래의 블렌드보다 가스 및 용제차단성, 내열성, 내약품성, 광학적 투명성 등을 보완시킨 라멜라사출성형공정이 개발됨으로써 성형업자들은 3종 또는 그 이상의 다른 폴리머들을 직접 사출성형하여 통상적인 블렌드공정에 비해 물성을 크게 향상시킬 수 있게 되었다.

• 기계와재료
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• v.15 no.3 s.57
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• pp.90-97
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• 2003