• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.786-791
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• 2000

The purpose of this study is to investigate quantitatively the effects of drawbead dimensions to the weld line movements for the deep drawing of the tailor welded blanks. Square blanks have been used and five different circular drawbeads were installed in experimental apparatus. The differences in the weld-line movements and the tendencies of the strain distributions in thickness were investigated by experimental and analytical methods. The results of the weldline movement show that the smaller the radius of drawbead installed, the larger the values of movements. Also it is shown for thickness strain in central and diagonal direction that the larger the dimension of drawbead, the larger the values of maximum thickness strain. The drawbead adds the additional restraining forces to the blank, hence the movement of weld line could be controlled by the adequate drawbead installation

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2002년도 금형가공 심포지엄
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• pp.136-143
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• 2002

Warm draw die technique which is one of the new forming technologies to improve formability of sheet metal is applied to the cylindrical and square cup drawing of stainless-aluminum clad sheets. In experiments the temperature of die and blank holder is varied from room temperature to $180^{\circ}C$, while the punch is cooled by circulation of coolant to increase the fracture strength of workpiece on the punch comer area. Test materials chosen for experiments are STS304-A1050-STS304 clad sheets. Teflon film as a lubricant is used on both sides of a workpiece. The limit drawing ratio and relative drawing depth as well as quality of drawn cups(distribution of thickness)are investigated and validity of warm drawing process is also discussed. No separation between each laminated material after drawing occurred through inspection by microscope as well as application of penetrant remover and bond strength test. Therefore, warm forming technique was confirmed to give better results in deep drawing of stainless clad sheet metal.

• 소성∙가공
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• 제5권1호
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• pp.8-17
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• 1996

In the present study SEAM (Shear Energy Augmented Membrane) elements have been devel-oped. Maintaining the numerical efficiency of conventional membrane elements the effect of out-of-plane deformation (transverse shear deformation) has been incorporated for the purpose of computational stabilization without introducing additional degrees of freedom. Computations are carried out for the deep drawings of square cup to check the validity and the effectiveness of proposed SEAM elements. The computational results are compared with both the existing results. And the effects of process variables like initial sheet thickness punch & die round and clearance are checked

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.281-281
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• 2007

• 소성∙가공
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• 제9권5호
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• pp.526-532
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• 2000

Springback simulation is receiving increasing attention throughout the automotive industry and the academic world. The knowledge of the real springback of stamped parts can help the stamping technicians to modify the process parameters or die geometry in order to reduce the shape defect. This paper presents the results of springback simulation after aluminium square cup deep drawing and trimming simulation, and results of springback optimization using response surface method.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 추계학술대회논문집
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• pp.76-79
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• 1997

In this study, an elasto-plastic finite element code, ESFORM, was developed to analyze sheet stamping processes. A formulation of 4-node degenerated shell element was implemented in the code. Workpiece materials were assumed to have planar anisotropy, and governed by associated flow rule. Explicit time integration method was employed to save computation time and reduce the required computer memory. Penalty method was used to describe interface behavior between workpiece and rigid die. Deep drawing of square cup and front finder stamping processes were simulated by ESFORM>

• 한국산학기술학회논문지
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• 제18권6호
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• pp.330-335
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• 2017

최근 자동차 산업에서 전기 모터 연료 전지에 대한 수요가 급증했으며, 연료 전지 케이스로 사용되는 사각형 알루미늄 캔에 대한 수요 또한 증가하고 있다. 직사각형 배터리 케이스의 바닥에 있는 에어 벤트는 비정상적으로 높은 압력이 발생할 때 미리 압력을 방출하여 큰 폭발을 방지하는 역할을 한다. 직사각형 컵 배터리 케이스는 6 단계의 다단계 딥 드로잉으로 외형을 만들고 직사각형 배터리 케이스와 용접하여 벤트 부품을 제작해왔다. 그러나 본 연구에서는 직사각형 케이스의 바닥면에 공기 벤트 형상을 직접 추가 하는 연구를 수행하였다. 단조의 초기 형상으로는 사각 컵 다단식 딥 드로잉 성형 해석에서 추출한 두께와 형상을 이용한 유한 요소 해석 기법을 사용 하였다. 그 결과, 예측 정밀도가 향상되고, 배부름 및 파단 등의 결함을 미리 예측할 수 있었다. 초기 분석 결과를 토대로 두 가지 단조 형상이 후보로 제시되었고 성형 해석을 통해 최적의 단조 형상을 결정 하였다. 이러한 결과를 바탕으로 금형을 제작하고 실제 결과와 분석 결과를 비교하여 본 연구의 타당성을 검증하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.641-645
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• 2002

In case of aluminum-cased battery, The ratio of height and base of square is generally above the ten times, square-shaped and problem of non-axis symmetry. It is typical model to set up the analysis method of finite element. The reliable analysis of finite element method is suggested, which is used to investigate the possibility that multi-stage deep drawing and ironing used currently is replaced by backward impact extrusion favorable in the respect of cost production and productivity. The influence of parameter was analyzed and compared, which was considered to analyze the process of large deformation plasticity such as extrusion. Die and billet was made as the same shape of finite element model. The results of experiment show good forming without the rupture and wrinkles with the optimum velocity 100mm/sec obtained by analysis.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.301-301
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• 2000

It is well known, for many years, that deep drawability ,can be improved by applying variable blank holding force. To apply variable blank holding force during cup during, we set up pressure controlling system on experimental hydraulic press, and the pressure control system is often called NC(Numerically Controlled} cushion system. Using the NC cushion system we carry out pressure control experiment and the proposed structure shows good performance. And we compare drawability of square steel cups with NC cushion and that with conventional cushion. The results show drawability is greatly improved when the pressure control curve is designed in a S-shaped curve. This paper includes design details of the NC cushion system and experimental analysis of drawability with experimental NC cushion system.

• 한국산학기술학회논문지
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• 제18권3호
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• pp.320-326
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• 2017

다단 딥드로잉 기술은 제품의 생산성 향상과 비용 절감을 위해 휴대폰 배터리 케이스 제품의 생산 공정으로 많이 사용하고 있다. 휴대폰 배터리 케이스는 용량과 강성을 목적으로 세장비가 큰 사각 컵 형상으로 제조된다. 사각 컵 형상의 다단 딥드로잉은 세장비가 크고, 복잡한 변형 형태 메커니즘으로 인한 제품의 좌우 높이 차이가 발생한다. 이로 인해 제품 조립과 표면 품질에 문제가 발생한다. 본 연구에서는 이러한 문제를 개선하기 위해 제품의 높이 차이가 최소가 되는 블랭크 형상에 대해 연구했다. 제품 좌우 높이 차이가 최소가 되는 블랭크 형상을 찾기 위해 최적 설계와 해석을 수행했다. 타원형 블랭크의 장변과 단변을 설계 변수로 설정하고, 목적 함수는 높이 차이가 최소가 되도록, 제품의 두께 감소율이 목표 범위에 도달하도록 설정했다. 또한 최종 제품 형상의 높이를 구속 조건으로 설정하였다. 그 결과 최적 설계를 통한 초기 블랭크 설계로 높이 차이가 최소가 되었으며, 원하는 공정을 지정하여 높이 차이가 최소화 되도록 수행 가능하다. 향후 개발된 자동화 프로세스로 인해 모든 각형 타입의 초기 소재 설계가 가능할 것으로 판단된다.