• 한국공작기계학회논문집
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• 제16권5호
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• pp.166-171
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• 2007

In this paper Research development about a micro metal forming manufacturing system has been developed. A micro forming system has been achieved in Japan and it's developed micro press is limited to single forming process. To coincide with the purpose to be more practical, research and development is necessary about the press which the multi forming process is possible. We set the development of the equipment including micro deep drawing, micro punching and micro restriking process to the goal. To achieve this goal, we set the application product to a micro thin foil valve which is used in the micro pump module. The compound die set has been designed and manufactured to make two step process. The material of thin foil valve is SUS-304 and its thickness is 50$\mu$m. We can get a good forming results from micro punching experiments in this paper.

• 조명전기설비학회논문지
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• 제18권3호
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• pp.90-94
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• 2004

본 논문에서는 고주파 공진형 인버터를 이용하여 유도가열(Induction Heating)용 고주파 공진형 인버터와 고주파로 인한 표피효과(Skin effect)에 관하여 설명하였다. 그리고 실험기구를 제작하여 상자성체의 대표적 금속인 알루미늄을 사용하여 유도가열과 표피효과의 현상을 확인하였으며, 알루미늄 박판 가열의 가능성과 활용방안에 대하여 제안하였다.

• 소성∙가공
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• 제6권4호
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• pp.300-310
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• 1997

A finite element inverse method is introduced for direct prediction of blank shapes, strain distributions, and reliable intermediate shapes from desired final shapes in axisymmetric multi-step deep drawing processes. This mothod enables the determination of process disign. The approach deals with the Hencky's deformation theory. Hill's second order yield criterion, simplified boundary conditions, and minimization of plastic work with constraints. The algorithm developed is applied to motor case forming, and cylindrical cup drawing with the large limit drawing ratio so that it confirms its validity by demonstrating resonably accurate numerical results of each problem. Numerical examples reveal the reason of difficulties in motor case forming with corresponding limit diagrams.

• 대한금속재료학회지
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• 제49권8호
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• pp.642-648
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• 2011

This paper describes an experimental study on ultrasonic welding of similar and dissimilar metals. There are optimum welding conditions which are found for welding of Al/Al and Al/Cu. It evaluated weldability using tensile test, SEM observation and EDX-ray analysis. Both ultrasonic welding of Al/Al and Al/Cu have amplitude as the variable factor. Al/Cu welding was examined again with welding time as variable factor to find the best conditions. The more welding time or amplitude increase, the better weldability. The optimum conditions for ultrasonic welding of Al/Al were formed at pressure 0.25 MPa, welding time 0.25 sec, amplitude 90%. Pressure 0.25 MPa, welding time 0.4 sec, amplitude 80% are optimized for Al/Cu ultrasonic metal welding and solid-state diffusion generated by ultrasonic vibration and frictional heat is confirmed at the welded interface.

• 대한금속재료학회지
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• 제46권3호
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• pp.135-143
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• 2008

The inhomogeneous texture through the thickness direction can be developed during hot rolling deformation in aluminum alloy. In this study, the inhomogeneous texture evolution through the thickness direction during hot rolling deformation in Al-5 wt%Mg alloy produced by a new strip casting technology was measured experimentally. Macrotexture measurement was conducted using X-ray diffractometer. A finite element analysis with ABAQUS/StandardTM and rate sensitive polycrystal model were used to predict the evolution of hot rolling texture. The experimental results of Al-5 wt%Mg alloy were compared with calculated results. The shear texture components tend to be increased at the surface region of the hot-rolled specimen. It is found that triclinic sample symmetry is more accurate assumption for texture analysis and simulation in the surface region of hot-rolled aluminum alloy.

• 대한기계학회논문집A
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• 제34권12호
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• pp.1805-1810
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• 2010

본 논문에서는 알루미늄 박판의 다단 전해식각을 공정을 이용한 3 차원 마이크로 구조물 제작방법을 제안한다. 본 공정은 기존 전해가공 공정들에 비해 3 차원 구조물의 대량생산이 용이하며, 기존 3 차원 마이크로 금속 구조물의 제작을 위한 다단 도금방법에 비해 간단하고, 경제적일 뿐만 아니라, 성형된 금속 박판을 이용하므로 구조물의 물성이 안정적이다. 본 논문에서는 단일 전해식각 공정을 통한 2 차원 외팔보 열과 다단 전해식각 공정을 통한 3 차원 마이크로 구조물의 제작을 수행하였다. 단일 전해식각 공정에서 평균 수직방향 식각률 $1.50{\pm}0.10 {\mu}m/min$ 와 평균 수평방향 식각률 $0.77{\pm}0.03 {\mu}m/min$을 얻었으며, 이를 이용한 3 차원 마이크로 구조물을 제작한 결과, 수직방향으로 $15.5{\pm}5.8 %$, 수평방향으로 $3.3{\pm}0.9 %$의 제작오차와 $37.4{\pm}9.6 nm$의 표면조도를 보였다.

• 한국산학기술학회논문지
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• 제11권12호
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• pp.4735-4741
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• 2010

초음파 금속 용착은 신소재, 도금 구조물 등과 같은 다양한 재료의 용착에 대한 가능성 때문에 광범위한 분야에서 사용되고 있으며 용착 조건도 다양하다. 본 연구에서는, 이종 금속 박판의 초음파 금속 용착을 위해 설계된 단부가형 한파장 혼은 유한요소해석 하였다. 유한유소해석은 초음파 혼의 최적 설계와 초음파 공구혼의 고유 주파수를 예상하기 위해 사용되었다. 그리고 설계된 한파장 스텝 혼은 고유 주파수 분석 시스템을 사용하여 실험적으로 검증하였다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.66-66
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• 2007

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 춘계학술대회논문집
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• pp.217-221
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• 1997

In this study, 3D sheet metal forming analysis program is developed by explicit finite element method. In this program, analysis flow just follows the real engineering process to provide the user intuitive understanding and smooth contact alorithm improves the accuracy of stress prediction. The capability of this program are demonstrated by various examples.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2003년도 춘계학술발표대회 개요집
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• pp.228-230
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• 2003

Recently, lots of joining methods of thin metal sheets are being developed in order to improve joint quality and productivity in manufacturing area. Current existing welding methods are continuously challenged as new materials and smaller thickness of metal sheets are required. In this study, laser plug brazing process was investigated as a new joining method of thin metal sheets. A CO2 laser system with automatic feeding of filler metal wire and flux was developed, and laser plug brazing experiments were conducted. The brazed joints were analyzed using various methods.