• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.1
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• pp.96-105
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• 1994

Cup drawing tests were performed to evaluate the friction characteristics of sheet metals. The linear relationship between drawing force and blank holding force obtained from the cup drawing test was used to calculate the coefficient of friction of the sheet metal. The friction coefficient was compared to that from conventional draw bead friction test. It was clarified that the cup drawing test can be used as a simple and convenient method for evaluating the friction characteristic of the sheet metal and also lubricity of the lubricant used.

• Proceedings of the KAIS Fall Conference
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• 2011.12b
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• pp.614-616
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• 2011

본 연구에서는 유한요소법과 변형률 의존성 연성파괴이론을 이용하여 드로잉 공정에서의 AZ31 마그네슘 합금 판재의 파단 발생을 예측 하였다. 다양한 온도에서의 사각컵 드로잉 실험을 수행하여, 각 온도조건에서의 파단깊이를 측정하였으며, 고온 인장시험을 통해 연성파괴상수를 온도 및 변형률 속도에 의존적인 값으로 표현하고, 실험과 동일하게 모사된 유한요소해석을 수행하였다. 해석결과 얻어진 각 요소의 온도 및 변형률 속도에 따른 연성파괴상수를 이용하여 파단발생을 예측하였으며, 실험결과와 검증하였다.

• Journal of Power System Engineering
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• v.7 no.2
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• pp.61-65
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• 2003

Sheet metal forming process is a non-linearity problem which Is affected by various process variables, such as geometric shape of punch and die, frictional characteristic, etc.. Therefore, the knowledge of the influence of the process variables is needed in the design of sheet metal working processes. In this paper, deep drawing tests for blank holding force, punch speed and lubrication between sheet material and tool were carried out to investigate the influence upon sheet formability. Experimental results were discussed about the defects on the deformation behaviors during the forming process.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1593-1596
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• 2003

Sheet metal forming process is a non-linearity problem which is affected by various process variables, such as geometric shape of punch and die, frictional characteristic, etc.. Therefore, the knowledge of the influence of the process variables is needed in the design of sheet metal working processes. In this paper, deep drawing tests for blank holding force, punch speed and lubrication between sheet material and tool were carried out to investigate the influence upon sheet formability. Experimental results were discussed about the defects on the deformation behaviors during the forming process.

• Transactions of Materials Processing
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• v.3 no.1
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• pp.51-62
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• 1994

Cup drawing test and U-bending test were performed to evaluate the friction characteristics of sheet materials for the different deformation modes involved in stamping process. The coefficient of friction calculated from the each test was compared to that obtained from the draw bead friction test. It was clarified that the cup drawing test could be simply used for evaluating the friction characteristic of sheet material in deep drawing process with high contacting pressure. However the U-bending test is suitable to evaluate the frictional characteristic of sheet material in bending process with low contacting pressure.

• Transactions of Materials Processing
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• v.8 no.5
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• pp.449-453
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• 1999

Sheet metal forming process is a non-linearity problem which is affected by various process variables, such as geometric shape of punch and die, frictional characteristic, etc.. Therefore, the knowledge of the influence of the process variables is needed in the design of sheet metal working processes. In this paper, cylindrical cup drawing tests for blank holding force, punch speed and lubrication between sheet material and tool were carried out to investigate the influence upon sheet formability. Experimental results were discussed about the defects on the deformation behaviors during the forming process.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.1
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• pp.51-61
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• 1993

A systematic approach of the energy method is proposed for analysis of axisymmetric deep drawing in which the total deforming region is divided into five sections by the geometric characteristic. The corresponding solution is found through optimization of the total energy dissipation with respect to some parameters assumed in the kinematically admissible velocity field defined over each region. The sheet blank is divided into three-or five-layers to consider the bending effect. For the evaluation of frictional energy, it is assumed that the blank holding force acts on the outer rim of the flange and that the contact pressure acting on punch shoulder or die shoulder has uniform distributions, respectively. The computed results by the present method are compared with the experiment and the computed results by the elastic-plastic finite element method for the distribution of thickness strain and the relation between the punch stroke and punch load. The results for the case of multi-layers show better agreements than for the case of a single layer in load vs. stroke relation and strain distribution. It is thus shown that the multi-layer technique can be effectively employed in analyzing axisymmetric deep drawing in connection with the energy method.

• Journal of the Korean Institute of Gas
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• v.20 no.4
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• pp.78-84
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• 2016

In this work, finite element investigations were carried out to optimize reverse drawing process design for manufacture of high-capacity aluminum liner used in fuel cell vehicle. The tensile tests with aluminum alloy Al6061 annealed at $350^{\circ}C$ were carried out to obtain the flow stresses. In order to estimate more accurate flow stresses after necking, the flow stresses were estimated from the comparison of load vs. displacement curves which were obtained from experimental and simulation results of tensile tests. In case of finite element analyses of reverse drawing processes, it was focused on the effects of process designs such as punch and die designs, blank holding force, drawing ratio and the clearance between the punch and blank holder on the generation of wrinkle and fracture of the blank and partially heated punch. However, it was revealed that experimental results still show the fracture at the end of 2nd drawn cup, although partially heated punch is used. Nevertheless, the drawn cup can be used because the sufficient length of the drawn cup for the next flow forming process and spinning process was obtained.

• Transactions of Materials Processing
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• v.10 no.6
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• pp.471-477
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• 2001

Milli-structure components are classified as a component group whose size is between macro and micro scales, that is, about smaller than 20mm and larger than 1mm. The forming of these components has a typical phenomenon of bulk deformation with thin sheets because of the forming size. In this study, milli-structure rectangular cup drawing is analyzed and measured using the finite element method and experiments. Special containers or cases of cellular phone vibrator to save installation space are produced by rectangular-shaped drawing. A systematic approach is established for the design and the experiment of the forming processes for rectangular milli-structure cases. To verify the simulation results, the experimental investigations were also carried out on a real industrial product. The numerical analysis by FEM shows good agreement with the experimental results in view of the deformation shape of the product.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.471-476
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• 2001

Milli-structure components ate classified as a component group whose size is between macro and micro scales, that is, about less than 20mm and larger than 1mm. The forming of these components has a typical phenomenon of bulk deformation with thin sheets because of the forming size. In this study, milli-structure rectangular cup drawing is analyzed and measured using the finite element method and experiment. Generally, milli-structure containers or cases like cellular phone vibrator consist of rectangular-shaped drawing to save installation space. A systematic approach is established for the design and the experiment of the forming processes for rectangular milli-structure cases. To verify the simulation results, the experimental investigations were also carried out on a real industrial product. The numerical analysis by FEM shows good agreement with the experimental results in view of the deformation shape of the product.