• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.318-321
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• 2005

The shell part is made of 2-layered blank because of functional requirements. To investigate the draw formability in this kind of part, the 2-layered sheet metal forming analysis process should be stipulated. First of all, treatment of contact with each blank must be considered to prevent the penetration on the each blank. Subsequently, applying the draw bead force is considered carefully because application of drawbead force for analysis is different with equivalent drawbead force. Formability as like crack, neck and wrinkles is estimated by FLD(Forming Limit Diagram) and thinning. A feasibility of the 2-layered sheet metal forming analysis process study is verified compare 2-layered sheet metal forming analysis with experimental results.

• Transactions of Materials Processing
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• v.28 no.1
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• pp.5-14
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• 2019

In order to reduce the weight of automobile parts, automobile parts using aluminum alloy are being developed. Aluminum alloy for automobile parts is mainly made of Al6xxx (Al-Mg-Si) type alloy, which is excellent in hot forming property, and it can increase mechanical properties by the use of heat treatment. In this study, hot forming was performed using Al6082. Before the hot forming, the forming analysis was performed using the DEFORM-3D finite element analysis program in this case. For the forming analysis, the heat transfer coefficient was derived from the experiment, and the forming analysis was performed by applying it. At the forging analysis, the temperature of Al6082 material was set to 813K and that of the mold was set to room temperature. After the forging analysis, the experiment was performed, and the forging analysis and the experimental results were compared.

• Transactions of Materials Processing
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• v.13 no.2
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• pp.129-136
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• 2004

Recently, instead of a matched die forming method requiring a high cost and long delivery term, a multi-point dieless forming method using a pair of matrix type punch array as flexible dies has been developed. Since the conventional multi-point dieless forming method has some disadvantages of difficulty in precise punch control and high-cost of equipment, a new concept of multi-point dieless forming method combined with an elasto-forming method has been suggested in this study. For optimal selection of elastomers, compression tests of rubbers, polyethylene and foams were carried out together with FEM analysis of the deformation behavior during sheet forming process using a rigid punch and elastomers. Compressive strain was concentrated on the upper central area of the elastomer under the punch, and the rubber exhibited higher concentration of the compressive strain than foams. Two-dimensional curved surface was formed successfully by the multi-point elasto-dieless forming method using an optimal combination of rubber and foam materials.

• International Journal of Precision Engineering and Manufacturing
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• v.6 no.2
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• pp.26-33
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• 2005

In this paper, the tube forming by radial-forward extrusion is analyzed by numerical simulation and experiments. The paper discusses the effect of process variables such as gap height, relative gap width and die comer radius on tube forming. The influence of deformation patterns of flange in radial extrusion on forward extrusion for tube forming is investigated and summarized in terms of the maximum forming force and hardness variations along the extrusion path. Furthermore the external defects are shown experimentally during the forming operation. Based on finite element analysis in conjunction with experimental test in Al alloy, analysis is performed for important parameter combination in order to reduce forming defects. Eventually, the process parameters for safe forming are suggested in order to reduce the forming defects.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.12
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• pp.168-175
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• 2003

In this paper, the tube forming by radial-forward extrusion is analyzed by numerical simulation and experiments. The paper discusses the effects of process variables such as gap height, relative gap width and die corner radius on tube forming. The influence of deformation patterns of flange in radial extrusion on forward extrusion for tube forming is investigated and summarized in terms of the maximum forming force and hardness variations along the extrusion path. Furthermore the external defects are shown experimentally during the forming operation. Based on finite element analysis in conjunction with experimental test in Al alloy, analysis is performed for important parameter combination in order to reduce forming defects. Eventually, the process parameters for safe forming are suggested in order to reduce the forming defects.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.08a
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• pp.21-28
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• 2003

Recently, instead of a matched die forming method requiring a high cost and long deliverly ten a multi-point dieless forming method using a pair of matrix type punch array as flexible dies has been developed. As this multi-point dieless forming method has some disadvantage of difficulty in precise punch control and high-cost of equipment, a new concept of multi-point dieless forming method combined with elastomer forming was suggested in this study. For optimal selection of elastomers, compression tests of rubbers, polyethylene and foams were carried out together with FEM analysis of the deformation behavior during sheet forming process using a rigid punch and elastomers. Compressive strain was concentrated on the upper central area of the elastomer under the punch, and the rubber exhibited higher concentration of the compressive strain than foams. Two-dimensional curved surface was formed successfully by the multi-point elasto-dieless forming method using an optimal combination of a rubber and foam.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.4
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• pp.121-126
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• 2011

An accumulator placed on the refrigerant cycle pipe lines is a part to relax fluctuations of pressure within the pipe lines and stabilize refrigerants flowed into pipe. The accumulator has been mainly manufactured by the process of tube spinning using CNC(Computer Numerical Control) lathe. However, this process has the defects which are low productivity per hour and high cost. For that reason, tube end-forming using roll die is actively being developed, recently. The purpose of this study is to develope the tube end-forming process using roll die in order to manufacture the accumulator for the refrigeration pipe lines. First, the process design of tube end-forming was performed based on specification of product, and then was verified with FE analysis. Also, the effects of friction coefficient and revolution speed of roll die on forming load were investigated. The analytical results were applied in the final process design of tube end-forming. Finally, tube end-forming test was carried out to verify the validity of the FE analysis and the process design.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.265-268
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• 2006

The superplastic forming/diffusion bonding is widely accepted as an advanced technique for forming complex industrial components. But the superplastic forming process requires much forming time and generates excessive thinning thickness distribution of formed part. Superplastic in materials is only achieved in a narrow range of strain-rate with optimum value unique to each material. In this study, finite element analysis for surperplastic forming/diffusion bonding (SPF/DB) processes of three-sheet and four-sheet sandwich parts. From this study, forming analysis have offered a lot of information for developing the forming process.

• Transactions of Materials Processing
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• v.19 no.3
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• pp.167-172
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• 2010

Roll-to-roll forming process is one of important metal processing technology because the process is simple and economical. These days, with these merits, roll-to-roll forming process is tried to be employed in manufacturing the circuit board, barrier ribs and solar cell plate. However, it is difficult to apply to the forming of micro scale or sub-micro scale pattern. In this study, the roll forming processing for the micro scale is designed and analyzed. The forming of micro pattern for small electric device such as LCD panel by incremental roll forming process is analyzed. Firstly, the optimum analysis conditions are found by several analyses. And then, formability is analyzed for various protrusion shapes at various forming temperatures. The formability is evaluated in terms of filling ratio and damage value. The filling ratio is defined from the tool geometry and critical damage is determined from the analysis of uniaxial tensile test. Finally, optimum forming conditions that guarantee the successful forming are found.

• Transactions of Materials Processing
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• v.15 no.8 s.89
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• pp.556-561
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• 2006

Most of auto-body members are composed of stamping parts. These parts have the non-uniform thickness and plastic work hardening distribution during the forming process. This paper is concerned with the side impact analysis of the ULSAB-AVC model according to the US-SINCAP in order to compare the crashworthiness between the model with and without considering the forming effect. The forming effect is ca]ciliated by one-step forming analysis for several members. The crashworthiness is investigated by comparing the deformed shape of the cabin room the energy absorption characteristics and the intrusion velocity of a car. The result of the crash analysis demonstrates that the crash mode, the load-carrying capacity and energy absorption can be affected by the forming effect. It is noted that the design of an autobody should be carried out considering the forming effect for accurate assessment of crashworthiness.