• Transactions of Materials Processing
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• v.6 no.3
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• pp.203-212
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• 1997

In this research, to obtain the optimal die width of CV die(conventional die), which replaces FM die in free forging of large scale rotor using the flat die, the model material experiments and theoretical analysis using three dimensional FEM are performed. The FM die, which was designed to remove Mannesmann's effect at the central part of the ingot, has very bad workabiltity in real field, therefore on the empirical base they use the CV die of wide width in actual working field. In this study, the excellency of CV die is proved quantitively, and the optimal die width of CV die is determined through the model material experiments and theoretical analysis using FEM in the point of effective strain, stresses, and load.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.1
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• pp.33-41
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• 2010

This study was aimed at the design of the dies for the unified pipe joint of the intermediate shaft using the computer simulation to shorten the period of production, on the basis of the process planning which was designed by the field experts. In the computer simulation, 'Deform-3d' and 'eesy-DieOpt' have been used, which are the commercial process analysis and die design program. Through the process analysis, we could know the propriety of the forming process, the inner pressure of the die and the suitable fitting pressure between the insert and the sleeve which was not showing any positive tangential stresses in the insert. Through the simulation of die design, we could know the number of the stress ring, the diameter ratios, the stresses of the die, the shrink fitting tolerance and temperature in the condition of the already determined maximum outer die diameter of the multi-stage former. The validity of the die design using the computer simulation was analyzed by the experiments and the results were satisfactory. As the results of this study, the new and easy die design system for multi-forging has been developed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.118-121
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• 2008

Flexible die is more efficacious than fixed die which is generally used in stretch forming process in view of production cost. Accordingly, in order to verily the validity of the flexible forming process, curved thin skin structure forming analyses using the fixed and flexible die were performed. As results, merit and demerit with regard to the fixed and flexible die were confirmed. The result of the stretch forming process analysis using the flexible die was better than that using the fixed die in view of the elastic recovery. However wrinkles were occurred on the sheet material due to die cavities between the punches in the flexible forming process, thus the solutions against these problems were presented.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.7
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• pp.1073-1080
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• 1997

The stage 1 compaction behavior of tool steel powder under die pressing was studied. The friction effects between the powder and the die wall under different die pressing modes were also investigated. The elastoplastic constitutive equations based on the yield functions by Fleck et al. and by Shima and Oyane were implemented into a finite element program to simulate die compaction processes. Finite element calculations were compared with experimental data for densification and density distribution of tool steel powder under single and double action die pressing. Finite element calculations using the yield function by Fleck et al. agreed better with experimental data than by Shima and Oyane.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.11a
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• pp.45-53
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• 2001

Copper bus-bar is made by drawing process and used in many part of industry. When design drawing die for copper bus-bar, design factor is focused on the deformation of die-land by drawing force and shrink fit. In this paper, to determine shrink fit value is analyzed by automatic shrink fit analysis program, APDL/UIDL language in a commercial FEM package, ANSYS, has been developed that enables optimal design of the dies taking into account the elastic deflections generated in shrink fitting the die inserts and that caused by the stresses generated in the process and by using DEFORM software for drawing process analysis. This data can be processed as load input data for a finite element die-stress analysis. Process simulation and stress analysis are thus combined during the drawing die design. The stress analysis of the dies is used to determine optimized dimension of die-land.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.6
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• pp.1893-1902
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• 1996

Densification behavior of 316L stainless steel power under die pressing was studied. The efects of friction between the powder and die wall under different die pressing modes were also investigated. The elastoplastic constitutive equations based on the yield functions of Fleck-Gurson and of Shima and Oyane were implemented into finite element program(ABAQUS) to simulate die compaction processes. The finite element results were compared with experimental data for 316L stainless steel powder under die pressing.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1992.03a
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• pp.103-114
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• 1992

Cogging is generally the initial and primary step in the manufacture of practically all large open-die forgings, and consists of forging and ingot by reducing the cross-section and simultaneously enlarging the body. A three-dimensional thermo-viscoplastic finite element model is used to study the distribution of internal stresses and strains of workpiece and temperature of workpiece and die during cogging process. Simulations are carried out on an circular ingot, using v-die and flat die, to study the effects of die configuration, die width, penetration depth, temperature gradient, die overlapping and pass design.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.61-64
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• 2003

In the field of automobile industry, suspension parts have been fabricated by the light metal part to substitute the steel part. For application light metal of suspension parts, mechanical property of high strength was performed. For anting semi-solid die casting of suspension part, die filling and solidification simulation have been carried out with Ostwald-de Waele rheological model. We designed the optimal die and secured injection condition as possible as laminar flow based on the result of computer simulation. Mechanical properties of knuckle part and heat treatment condition were investigated.

• Transactions of Materials Processing
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• v.11 no.4
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• pp.312-322
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• 2002

In this study, an innovative semi-solid die casting technology to replace heavier cast iron compressor parts with lightweight aluminum castings was proposed, and the application possibility for home-appliance component was investigated. The most important factors regarding the semi-solid die casting process are the reheating process of the raw materials to the semi-solid state, specifications of the forming machine, the optimal injection conditions and die design. Materials used in this study were A3S7 and hSn alloys fabricated by the electromagnetic stirring process. The optimal injection conditions for semi-solid die casting process were Presented with the reheating conditions of the semi-solid materials. To investigate the effect of plunger tip shape on the formability and mechanical properties in semi-solid die casting process for complicated shape part, two kinds of plunger tip shape with long and short plunger tip taper are proposed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10b
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• pp.63-66
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• 2003

Forged gears have the obvious advantages with the greater utilisation of raw material and high productivity over the machined gears. The forged bevel gear has been used in differential gear for automotive with a high reliance. On the other hand, the studies have been continued to improve the accuracy and expand the applying areas. In this paper, a whole manufacturing process for forged gear from die design and cold forging to heat-treatment was introduced. The stress and elastic deformation for forging die have been analysed by the 3D-FEM-package. The real elastic deformation of die was measured by the strain-gages. The elastic deformation of die was reached to 1mm, in terms of the present study. The analysed quantitative dimension of die was taken into consideration into the CAD/CAM data for forging die.