• 소성∙가공
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• 제17권3호
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• pp.170-181
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• 2008

The shape of rectangular cup used for Ni-MH(Nickel-coated Metal Hydrogen) battery for hybrid car looks quite simple, but the forming process of extruding and setting up process design are highly difficult. Furthermore, there are few concrete reports on the rectangular deep drawn cup as part of hybrid vehicles till now. In this study, process design for rectangular cup in the multi-stage deep drawing process is carried out, and FE analysis is also preformed based on the result of the process design. From the simulation result, some unexpected problems such as earing, wrinkling and excessive thickness changes of the intermediate blank occurred. To overcome these failures, a series of modification for punch shape in the forming process design are completed and applied. Considering the modified punch shape in the multi-stage deep drawing process, additional FE analysis is also carried out and the simulation result is verified in view of the deformed shape, thickness change and effective strain distribution. The result of FE analysis with the improved process design confirmed not only reducing thinning of wall and possibilities of failure but also improving the quality of drawing product through the modification of punch shape.

• 대한기계학회논문집A
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• 제26권6호
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• pp.1077-1084
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• 2002

Optimum tool design is carried out fur a multi-stage rectangular cup deep-drawing and ironing process with the large aspect ratio. Finite element simulation is carried out to investigate deformation mechanisms with the initial design made by an expert. The analysis considers the deep drawing process with ironing for the thickness control in the cup wall. The analysis reveals that the difference of the drawing ratio within the cross section and the irregular contact condition produce non-uniform metal flow to cause wrinkling and severe extension. For remedy, the modification guideline is proposed in the design of the tool and the process. Analysis results confirm that the modified tool design not only improves the quality of a deep-drawn product but also reduces the possibility of failure. The numerical result shows fair coincidence with the experimental one. After tryouts of the tool shape, the rectangular cup has been produced in the transfer press.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2000년도 추계학술대회 논문집
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• pp.105-108
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• 2000

Finite element analysis of a multi-stage deep drawing process is carried out for the die design of rectangular cup drawing with the large aspect ratio. Simulation is performed for thorough investigation of unfavorable mechanisms in the initial design. The analysis reveals that the difference of the drawing ratio and the irregular contact condition produces non-uniform metal flow to cause wrinkling and severe extension. In this paper, the modification guideline is proposed in the design of the process and the tool shape. The analysis result confirms that the modified design not only improves the quality of a deep-drawn product but also reduces the possibility of failure.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 춘계학술대회 논문집
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• pp.85-88
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• 2001

Examination of the die design is carried out for a multi-stage rectangular cup drawing process with the large aspect ratio with the aid of the finite element analysis. The analysis considers the deep drawing process with the ironing process for the thickness control in the cup wall. Simulation is performed to investigate the deformation mechanism in the initial design and the modified design. The analysis clarifies that the irregular cross section and the irregular contact condition produces unfavorable deformation. The analysis results show that the modified design improves the quality of a deep-drawn product with the low possibility of failure. The analysis result also shows good agreement with the experimental one.

• 소성∙가공
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• 제10권2호
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• pp.144-150
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• 2001

Tool design is introduced in a multi-stage rectangular cup drawing process with the large aspect ratio. Finite element simulation is carried out to investigate deformation mechanisms with the initial tool design. The analysis reveals that the difference of the drawing ratio and the irregular contact condition produces non-uniform metal flow to cause wrinkling and severe extension. For remedy, the modification guideline is proposed in the design of the tool and process. Analysis results confirm that the modified tool design not only improves the quality of a deep-drawn product but also reduces the possibility of failure.

• 한국자동차공학회논문집
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• 제2권1호
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• pp.84-95
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• 1994

The effects of punch and blank shapes in the rectangular cup drawing process are examined experimentally to improve the formabilities. For this purpose, three blank shapes which are h-bl., G-bl., and T-bl., and five punch shape factors which are the ratios of two adjacent side lengths in rectangular cross section are adopted. The constructing methods of the three blank shapes are as follows. The h-bl. is designed by slip-line theory, and the G-bl. is selected for the similar shape to the punch. The T-bl. is obtained by the drawing method which is introduced in the technical references. The five punch shape factors are selected for length/width=1, 1.25, 1.5, 1.75 and 2. The experimental procedures are performed for all the above forming conditions to investigate and compare the formabilities. As a result, it is verified experimentally that the rectangular cups drawn by the h-bl. are more ideal than those drawn by G-bl. and T-bl.. They have not only higher limiting drawing ratio, more uniformity in drawn cup heights and more ideal thickness distributions, but also need relatively less maximum drawing forces.

• 소성∙가공
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• 제10권6호
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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.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 추계학술대회 논문집
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• pp.81-84
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• 2001

An inverse finite element approach is employed for more capability to design the optimum blank shape from the desired final shape with small amount of computation time and effort. In some drawing or stamping simulation with inverse method, it is difficult to apply inverse scheme due to the large aspect ratio or steep vertical angle of inclination. The reason is that initial guesses are hard to make out with present method for those cases. In this paper, a direct mesh marring scheme to generate initial guess on the sliding constraint surface described by finite element patches is suggested for one step inverse analysis to calculate initial blank shape. Radial type mapping is adopted for the simulation of rectangular cup drawing process with large aspect ratio and parallel type mapping for the simulation of S-Rail forming process with steep vertical angle of inclination.

• 한국정밀공학회지
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• 제15권12호
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• pp.68-71
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• 1998

Rectangular deep drawing process is widely used in sheet metal forming. But there are various defects such as earring, wrinkling, tearing, etc. In order to avoid the defects, an optimum blank shape is required. But it has not been generalized to determine the optimum blank shape because deep drawing processes are involved in complex process parameters. So, it is very necessary to do research systematically about determining the optimum blank shape of deep drawing process. In this study a rectangular cup drawing test has been carried out to determine the optimum blank shape for various stainless steel sheets. From the test, a new blank model, which has no earring, is proposed.

• International Journal of Precision Engineering and Manufacturing
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• 제4권1호
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• pp.5-8
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• 2003

The rectangular deep drawing process is widely used in sheet metal forming, but there are various associated defects, such as earing, wrinkling, tearing, etc. In order to avoid such defects, an optimum blank shape is required. Such an optimum blank shape cannot be generalized because deep drawing processes are involved in complex process parameters. So, it is necessary to do systematic research to determine the optimum blank shape for the deep drawing process. In this study, a rectangular cup drawing test has been carried out to determine the optimum blank shape for various stainless steel sheets. From the test, a new blank model, which has no earing, is propsed.