• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.531-532
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• 2008

• Transactions of Materials Processing
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• v.24 no.2
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• pp.115-120
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• 2015

Deep drawing of cylindrical cups is one of the most fundamental and important processes in sheet metal forming. Circular cups are widely used in industrial fields such as automobile and electronic appliances. Some of these cups are formed by a one-stage process, others such as battery cases and beverage cans are made by a multi-stage process. In the current study the multi-stage deep drawing of aluminum sheet metal is examined. The process consists of two deep drawing operations followed by two ironing operations. The press die, which can be used for the four-stage forming process, was manufactured allowing punch and die components to be easily changed for various experiments. The rolling direction of both the sheet and the drawn cups was always positioned toward the horizontal x-direction on the die face to minimize experimental errors during the progressive forming. The dimensional accuracy of the cylindrical cups formed at each stage and the earing defect due to the anisotropy of sheet were investigated. The influence of anisotropy on the thickness distribution was also examined. Both the thickness and the outer diameter of the cups were measured and compared for each set of experimental conditions. It was found that the dimensional accuracy of cups rapidly improves by employing the ironing process and also by increasing the amount of ironing.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.06a
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• pp.191-198
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• 1994

A practical example of the axisymmetric deep drawing process is simulated by the elastic-plastic finite element analysis using updated Lagrangian approach considering the large deformation. An approach is suggested to solve the problem of the ductile fracture that may encounter during the deep drawing process. The result can be applied to the design of the die for the axisymmetric deep drawing.

• 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.

• Transactions of Materials Processing
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• v.7 no.5
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• pp.439-444
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• 1998

Recently many automotive parts have been made with stainless steels by deep drawing processes, But there are various problems occurred in deep drawing works of stainless steels compared with low carbon steels. For the severe deep drawing of complex cylindrical housing optimum process planning is required to eliminate intermediate annealing improve shape accuracy and maintain surface integrity without drawing defects such as tears wrinkles and scratches or galling. Therefore in this study a sample process planning of the severe of the severe deep drawing process is applied to a complex cylindrical housing needed for a 6 multi-stepped deep drawing of type STS 305 . A series of experiments are performed to investigate optimum process variables such as drawing rate radius and clearance. Through experiments the variations of the thickness strain distribution and hardness distribution in each drawing step are observed. Also the effects of other factors on formability such as drawing oil, blank holding force and die geometry are examined and discussed.

• Transactions of Materials Processing
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• v.14 no.7 s.79
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• pp.607-612
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• 2005

In this paper, warm deep drawing process with local heating and cooling technique was attempted to improve the formability of AZ31 magnesium alloy which is impossibly to form by conventional methods at room temperature by finite element method and experiment. For FE analysis, in first model with considering heat transfer, both die and blankholder were heated to 573K while the punch was kept at room temperature by cooling water. Also distribution of thickness and von Mises stress at room temperature and 498k for warm deep drawing were compared by FEM. Uniaxial tension tests at elevated temperature were done in order to obtain the temperature dependence of material constant under temperature of $293K\~573K$ and cross head velocity of $5\~500mm/min$. The phenomenological model for warm deep drawing process in this work was based on the hardening law and power law strain rate dependency. Deep drawing experiment were conducted at temperatures of room temperature, 373K, 423K, 473K, 498K, 523K, and 573K for the blank and deep drawing tools(holder and die) and at a punch speed of 10mm/min.

• 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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• 1998.06a
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• pp.57-64
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• 1998

The purpose of this research is to develop a CAD/CAM system for generation all kind of information such as, total drawing, sub assembly drawing, part drawing, detail drawing, part list, and NC data for machining by CNC lathe, Wire CUT, machining center. Through this study the CAD/CAM System for deep drawing transfer die in mechanical press process has been developed. The developed CAD system can generate the drawing of transfer die in mechanical press. Using these results from CAD system, it can generate the NC data to machine die's elements on the CAD system. This system can reduce design man-hours and human errors. In order to construct the system, it is used to automate the design process using knowledge base system. The developed system is based on the knowledge base system which is involved a lot of expert's technology in the practice field. Using AutoLISP language under the AutoCAD system, CTK customer language of SmartCAM is used as the overall CAD/CAM environment. Results of this system will be provide effective aids to the designer and manufacturer in this field.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.10
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• pp.879-886
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• 2016

Tractrix dies, used in the deep drawing process, can be used to form CNG pressure vessels without a blank holder. Previous studies had only applied tractrix profiles to perform the first deep drawing process of DDI; but an optimal design of the tractrix die that focuses on improving die life and reducing production cost has not been performed yet. In this study, finite element analyses of deep drawing processes were conducted according to heights of the tractrix die by using translating asymptotes. In addition, researchers analyzed von-Mises stresses at the part of stress concentration of the die according to the forming punch loads in order to propose an optimal tractrix die design.

• Transactions of Materials Processing
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• v.24 no.6
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• pp.400-404
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• 2015

For mass production of stamped parts, which require complicated in-press operations, it is always advisable to use a progressive die set. It is difficult to choose a progressive die set if the stamped parts need to be deep drawn and especially if they are unsymmetrical. Because unsymmetrical deep drawing parts are very sensitive to the effect of weight during moving to the next step, they are hard to exactly locate on the die face. An automotive seat side cushion panel is about 80mm high, unsymmetrical and its low edge needs hemming, so it is hard to produce even using a progressive die set. In the current paper a progressive stamping for seat side cushion panel was examined. Five strip bridges were considered to be strong enough to move to the next die as predicted by the CAE analysis.