• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.265-268
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• 2003

In the extrusion process, the working material is forced to flow through a die with the desired profile. In general, the width of an extruded section is limited to about an inch less than the diameter of the round billet. But through the lip die, material is spreaded to produce a wider extruded section than the diameter of round billet. In this study, the extrusion process of an aluminum plate using the lip die is investigated. The width of the extruded plate is 450mm that is formed from the round billet with a diameter of 250mm. The flow characteristic through the lip die is considered to produce the wide-extruded plate with a small billet using rigid plastic FE analysis. Based on the result of FE analysis, new designs of lip die are proposed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.386-390
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• 2006

In this paper, kinematic analysis of a double-action link-type die set for the enclosed die forging is carried out. Operational principle of the die set in the enclosed die forging is introduced in detail. A closed form solution of the relative velocity of the middle plate with respect to the upper plate is given. The effect of link lengths on both strokes and velocities is investigated.

• Transactions of Materials Processing
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• v.16 no.6
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• pp.452-456
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• 2007

Cold forging technology of a gear product is being interested in the dimensional accuracy, high stiffness and reduction of stress concentration. Especially it is needed to avoid the damage due to extremely high local pressure. Therefore it is important to reduce the high pressure in die design of cold forging. In this study, single die insert type and splitted die insert type are considered to recognize the notch effects in the die of sprocket forming. The stress concentration has been released at the notch area by the cushion effect in the splitted die insert.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.95-98
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• 1999

In this study, a method to find the optimal intermediate die geometry for the multi-stage drawing process for the rectangular rod from a round bar is proposed and a program using the proposed method is developed. On the stage of the design of the intermediate die geometry, the virtual die was constructed using the initial billet as a inlet of the drawing die and the final product as a exit of that and the virtual die was divided by the number of pass. Divided die was transformed into the rectangular one which is the intermediate die geometry for the multi-stage rectangular drawing process. In order to verify the application of the proposed method on the real industrial product, the drawing of the rectangular rod from a round which composed two stage has been performed and simulated by the three dimensional rigid plastic finite element method.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.11a
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• pp.23-32
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• 2002

The torsional forward extrusion is the process that is executed by punch travel and die rotation. The advantages of having the die rotation on this process are that forming load can be reduced and optimal die angle can be increased. This provides a possibility to extrude cold-worded material where a large extrusion force and die angle are required. Also, this process can improve the material properties owing to the high deformation and uniform strain distribution. The forming load and optimal die angle of this process are determined by the upper bound analysis using stream function and the optimization technique. To verify the theoretical result, we have carried out experiments and FE simulations using DEFORM3D.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.152-155
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• 2004

In the semi-solid die casting process, the important thing is the flow behaviors of semi-solid material. The flow patterns of semi-solid material can make the defects during die filling. To control of the flow patterns, is very important and difficult. In this paper, the flow behaviors of the semi-solid A356 alloy material during die filling at various die gate shapes has been observed with the grain size controlled material. The effects of the gate shape on the die filling characteristics were investigated. The filling tests in each plunger strokes were experimented, also simulated on the semi-solid material die casting process by MAGMAsofi. According to the filling tests and computer simulation, the effect of the gate shape on liquid segregation had been investigated.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.115-119
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• 2004

In the extrusion process, the working material is forced to flow through a die with the desired profile. In general, the width of an extruded section is limited to about an inch less than the diameter of the round billet. But through the lip die, material is spreaded to produce a wider extruded section than the diameter of round billet. In this study, the extrusion process of an aluminum plate using the lip die is investigated. The width of the extruded plate is 450mm that is formed from the round billet with a diameter of 250mm. The flow characteristic through the lip die is considered to produce the wide-extruded plate with a small billet using rigid plastic FE analysis. Based on the result of FE analysis, an optimized design of the lip die is then proposed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1996.03b
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• pp.138-144
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• 1996

In square die extrusion, flow guide and ide land play important roles for controlling the metal flow in die design. In the present work, the flow guide and the die land are considered for the die construction. Based on ALE description , rigid-viscoplastic finite element analysid is carried out to assess the effects of process and die design parameters. The thermal state affects greatly the product quality in hot extrusion. in the present work, the temperature distribution is also analyzed in theframwork of rigid-viscoplastic finite element computation. As a computational example, hot square die extrusion with flow guide and die land has been analyzed for the profile of a H section.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.06a
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• pp.33-40
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• 1998

In recent domestic automotive industry, applications of computer simulation to the manufacturing of stamping dies for inner and outer body panels which greatly affect durability and aesthetic quality of automobiles, have been increased. Enhancement of die quality, and reduction of total die manufacturing time and consequently manufacturing cost are the visible outcome. However, to successfully apply the result of simulation by a commercial package to the die manufacturing, development of an optimal die manufacturing process is required upon the completion of analysis of forte and shortcomings of available sheet metal forming softwares in the market. Based on the results of numerical analysis of front door outer panel forming, this paper evaluates the applicability of simulation results to the real die making for automotive body panels. Also, it attempts to select an optimal die manufacturing process including design, machining and tryout. Lastly, it discusses the expected effects by adopting the selected process in a real stamping die manufacturing facility.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1996.10a
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• pp.122-130
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• 1996

During the cold forming, due to high working pressure acting on the die surface, failure mechanics must be considered before die design. One of the main reasons of die failure in industrial application of metal forming technologies is wear. Die wear affects the tolerances of formed parts, metal flow and costs of process etc. The only way to control these failures is to develop methods which allow prediction of die wear and costs of process etc. The only way to control these failures is to develop methods which allow prediction of die wear and which are suited to be used in the design state in order to optimize the process. In this paper, the wear experiments to abtain the wear coefficients and the upsetting processes was accomplished to observe the wear phenomenon during the cold forming process. The analysis of upsetting processes was accomplished to observe the wear phenomenon during the cold forming process. The analysis of upsetting processes was accomplished by the rigid-plastic finite element method. The result from the deformation analysis was used to analyse the die wear during the processes and the predicted die wear profiles were compared with the measured die wear profiles.