• Transactions of Materials Processing
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• v.17 no.8
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• pp.586-593
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• 2008

In warm press forming of magnesium alloy sheet, it is important to control the sheet temperature by heating the sheet in closed die. When forming a commercial AZ31 magnesium alloy sheets which are 0.5mm and 1.0mm thick, respectively, time arriving at target temperature and temperature variation in magnesium alloy sheet have been investigated. The deep drawing process with rectangular shape alone at the first stage and with both circular and rectangular shapes at the second stage was employed. At the first stage, through deep drawing process with rectangular shape alone according to various forming temperature($150{\sim}350^{\circ}C$) and velocity($0.1{\sim}1.0mm/s$), optimum forming condition was obtained. At the second stage, deep drawing process with the circular and rectangular shapes were performed following deep drawn square cups with Limited Drawing Height(LDH) obtained at the first stage. Here, clearance which is defined a gap between the die and the punch including sheet was set to ratio of 20, 40 and 100% to thickness in sheet. Accordingly, temperature, velocities, and clearances suitable for forming were suggested through investigating the thickness variation of the product.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.70-76
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• 1999

Recently most of researches for deep drawing process using sheet metal have been performed on the formability of axisymmetric shape but there have not been any concrete reports on the formability of non-axisymmetric shape In addition the conventional shape radius of the punch and die has been determined by the trying-and-error using industrial experimence and post processing test and only approximate shape radius of the punch and die has been determined by the trying-and-error using industrial experience and post processing test and only approximate shape radius of the punch and die has been present So in this study the optimal shape radius of the punch and die in deep drawing process with biaxisymmetric blank shape would be proposed. Through the deep drawing experiment it is found that in order to obtain the optimal products especially shape radius of the punch and die in all processes is very important.

• Transactions of Materials Processing
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• v.9 no.2
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• pp.120-127
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• 2000

Recently, most of researches for sheet metal deep drawing process have been performed on the formability of axisymmetric shape, but there are not any concrete reports on the formability of non-axisymmetric shape. In addition, the conventional shape radius of the punch and die has been determined by trial-and-error using industrial experience and post processing test, and only approximate shape radius of the punch and die has been presented. In this study, the optimal shape radius of the punch and die in deep drawing process with biaxisymmetric blank shape is proposed. Through the deep drawing experiment, especially it is found that in order to obtain the optimal products, and improvement of formability can be researched by selection of such punch and die shape radius that gives an adequate thickness distribution in all processes.

• Transactions of Materials Processing
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• v.8 no.4
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• pp.356-363
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• 1999

This paper discusses some techniques for the determination of optimum blank size and pre-form design for multi-stepped deep drawing of oval shell. The deep drawing process of oval shape has been regarded as more difficult than that of cylindrical shell because of its complicated behavior of plastic deformation. But there is insufficient information in this area to carry out successful deep drawing work of irregular products such as oval, rectangular, and square shapes. In order to find the optimum conditions, the drawing apparatus for two kinds of pre-form design are built, a series of drawing experiments performed, and thickness stain distributions measured. From the results of thess suggested experiments, various optimum process variables are observed and discussed.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.12
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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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• v.4 no.1
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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.

• Transactions of Materials Processing
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• v.7 no.6
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• pp.519-529
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• 1998

In automotive industries the stamping of laser-welded blank gives many merits which bring about dimensional accuracy, strong body assembly and high productivity. However the welding of blanks with different thickness or/and different strength materials introduces many challenging formability problems for process development and tool design. in this paper the deformation characteristics for deep drawing process of laser-welded blank with different thickness sheets are investigated by experiment as well as by FEM simulation. The blank holding force ratio to avoid the movement of weld line was suggested and compared with the experimental result for cylindrical and rectangular cup drawing process. The optimal location of weld line in laser-welded blank with different thickness sheets is calculated to compensate for the movement of weld line on deep drawing process. In addition the effect of location of weld line on formability is clarified using FEM simulation.

• Transactions of Materials Processing
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• v.5 no.1
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• pp.61-71
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• 1996

A computer-aided process design system for axisymmetric deep drawing products has been developed. An approach to the system is based on the knowledge based system. Knowledges for the system are formulated from the plasticity theory handbooks experimental results and empirical knowhow of the field experts. the system is composed of four main modules such as geometrical design test & rectification and user modification. The input to the system is final sheet-metal object geometry and the output from the system is process sequence with intermedi-ate objects geometries and process parameters, such as drawing load blank holding force clearance cup-drawing coefficient.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.721-723
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• 2000

Deep Drawing공정은 2차원 박판(Sheet Metal)에 그림이나 글자를 인쇄한 다음, 박판을 다이에 고정하고 펀치로 눌러서 3차원의 제품을 생산하는 소성가공의 한 방법이다. 그러므로, 2차원 평면인 박판에 어떻게 적절히 인쇄하여, 가공 후의 3차원 제품에 원하는 그림과 글자가 나타나게 할 수 있는지가 문제가 되고 있다. 본 논문에서는 Deep Drawing공정을 거쳐 완성된 제품을 측정한 후, 형상 역공학(Reverse Engineering) 기술을 이용하여 측정 데이터(Measured Points Data)를 입력으로 하는 매개변수 곡면 (Parametric Surface)을 만들고, Deep Drawing공정 전의 박판에 대한 매개변수 곡면을 만든 다음 두 곡면간의 매핑을 통해 위의 문제점을 해결하고자 한다.

• Transactions of Materials Processing
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• v.11 no.8
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• pp.676-681
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• 2002

The square cup deep drawing simulations for hydraulic counter pressure deep drawing are carried out by the finite element method and the formability factors which affect to the formability in case of that process are investigated. As a result, it is found that the thickness distributions keep the higher quality than that of the conventional deep drawing, and the maximum pressure increased the thickness at the die profile regions of blank. But friction coefficient decreased the thickness at the same regions.