• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.253-257
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• 2001

This study reveals the sheet metal working with multi-forming type ultra precision process. They require analysis of many kinds of important factors, i.e. theory and practice of metal press working and its phenomena, die structure, machining condition for die making, die material, heat treatment of die components, know-how and so on. In this study, we designed and constructed a multi-forming ultra precision progressive die as a bending and drawing working of multi-stage and performed through the try out for thin sheet metal. This part I of papers related to the analysis of production part and strip process layout design through the metal forming simulation by DEFORM and IDEAS.

• Transactions of Materials Processing
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• v.14 no.8 s.80
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• pp.704-711
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• 2005

The influence of process parameters in drawn wire on residual stresses was investigated. Based on a FE-simulation of the wire drawing process, the effects of process parameters such as semi-die angle, reduction, friction coefficient and bearing length on the residual stresses were investigated. The validity of the FE-simulation results was verified by the comparison of the previous simulated results with experimental data. In this study, semi-die angle and die reduction have significant effect on the residual stresses at the surface of drawn wire. Several methods such as, addition of axial tension, application of skin pass, straightening in multi-roll straightener etc, were suggested in the previous studies to reduce the residual stresses. In this study, the results show that the concurrent application of skin pass with low die reduction and low semi-die angle at the final stage of drawing operation reduces dramatically the both axial and hoop residual stresses after drawing

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.337-340
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• 2008

The cross section shape of intermediate die is one of important parameters to obtain dimensional accuracy of final product in shaped drawing process. Until now it has been designed by the experience or trial and error of the expert. In this study, the cross section shape of intermediate die fur spline shape is determined by the electronic field analysis, shape factor method. The result of the electronic field analysis, shape factor method has been compared with that of the present method. The effects of cross section shape on the dimensional accuracy were investigated by using FE analysis. And then the multi-stage shaped drawing experiments were performed to verify the results of FE analysis. As a result, the cross section shape from the electronic field analysis had the good dimensional accuracy. The electronic field analysis can be used for the method to obtain the cross section shape of intermediate die in shaped drawing process.

• Transactions of Materials Processing
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• v.17 no.8
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• pp.627-632
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• 2008

The cross sectional shape of intermediate die is one of important parameters to improve dimensional accuracy of final product in shaped drawing process. Until now, it has been designed by the experience or trial and error of the expert. In this study, the cross sectional shape of intermediate die for spline shape is determined by the electric fields analysis and scale factor method. The result of the electric fields analysis and scale factor method have been compared with that of the expert method. The effects of cross sectional shape on the dimensional accuracy were investigated by using FE-simulation. And then the multi-stage shaped drawing experiments were performed to verify the results of FE-simulation. As a result, the cross sectional shape from the electric fields analysis and scale factor method had the good dimensional accuracy. These two methods can be used for the method to obtain the cross sectional shape of intermediate die in shaped drawing process.

• Transactions of Materials Processing
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• v.26 no.2
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• pp.79-86
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• 2017

In this study, the sheet metal forming process of the brake chamber head, which had a complex shape compared to the conventional head part, was investigated using finite element (FE) analysis. In order to prevent the forming failures such as necking and fracture, the multi-stage forming process was introduced. The forming process consisted of three steps: (1) first drawing, (2) second drawing, (3) final forming. Experimental and FE simulated results of the brake chamber head were compared, and the results showed that the required characteristics of the straightness and the wall thickness at each location were satisfied.

• Transactions of Materials Processing
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• v.29 no.5
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• pp.272-281
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• 2020

As the thickness of mobile communication devices is getting thinner, the size of the internal parts is also getting smaller. Among them, the battery case requires a high-level deep drawing technique because it has a rectangular shape with a large aspect ratio. In this study, the initial blank shape was optimized to minimize earing in a multi-stage deep drawing process using an artificial neural network(ANN). There has been no reported case of applying artificial neural network technology to the initial blank optimal design for a square case with large aspect ratio. The training data for ANN were obtained though simulation, and the model reliability was verified by performing comparative study with regression model using random sample test and goodness-of-fit test. Finally, the optimal design of the initial blank shape was performed through the verified ANN model.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.196-201
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• 2001

This study reveals the thin sheet metal process with multi-forming die that the name is progressive die, as a pilotless type, also high precision production part is made. They require analysis of many kinds of important factors, i.e. theory and practice of metal press working and its phenomena die structure, machining condition for die making, die material, heat treatment of die components, know-how and so on. In this study, we designed and constructed a multi-forming progressive die as a bending and drawing working of multi-stage and performed through the try out for thin sheet metal. Out of the characteristics of this paper that nothing might be ever seen before such as this type of research method on the all of processes of thin and high precision production part.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.347-352
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• 2002

The Cut off-type progressive die for U-bending production part is a very specific division. This study reveals the sheet metal forming process with multi-forming die by Center Carrier type feeding system. Through the FEM simulation by DEFORM, it was accepted to u-bending process as the first performance to design of strip process layout. The next process of die development was studied according to sequence of die development, i.e. die structure, machining condition for die making, die materials, heat treatment of die components, know-how and so on. The feature of this study is the die development of scrapless progressive die of multi-stage through the Modeling on the I-DEAS program, components drawing on the Auto-Lisp, CAD/CAM application, ordinary machine tool operating and revision by tryout.

• Transactions of Materials Processing
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• v.22 no.8
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• pp.442-449
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• 2013

The solenoid valve case of an 8-speed automatic transmission plays a role in maintaining the valve seal, which prevents an inflow of foreign substances into the transmission. The seal increases the reliability of the automatic transmission's performance. As a solution to pollution-related problems and to reduce fuel consumption, transmissions are being made with more gears to work more economically and have reduced fuel consumption. These newer transmission require greater dimensional tolerances and need to be manufactured with more precision. In the current study, the design of a multistage drawing considering both the product's height and limit draw ratio (LDR) of the material was performed using both a theoretical analysis and the expertise of industrial experts. The finite element modeling (FEM) simulation was performed using the commercial software, PAM-stamp, and tests of the dimensional measurements for a prototype were performed to verify the optimal progressive process.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.834-837
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• 2005

This study presents a study on the influence of process parameters(semi-die angle, die reduction, friction condition, and bearing length) in drawn wire on residual stresses were investigated using FE-analysis. In this study, semi-die angle and die reduction have a significant effect on the residual stresses at the surface of drawn wire. In the previous study, in order to reduce the residual stresses, several methods were suggested: addition of axial tension, application of skin pass, straightening in multi-roll straightener etc. In this study, it can be known that the concurrent application of skin pass with low die reduction and low semi-die angle at the final stage of drawing operation reduces dramatically the both axial and hoop residual stresses after drawing.