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Park, J.H.;Lee, K.H.;Kim, S.M.;Kim, H.J.;Kim, S.J.;Kim, B.M.
- Transactions of Materials Processing
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- v.24 no.5
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- pp.340-347
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- 2015
Multi-pass shape drawing is used to manufacture long products of arbitrary cross-sectional shapes. This process allows smooth surface finishes and closely controlled dimensions of the cross-sectional shape. Tube shape drawing for hollow type products provides material savings and weight reduction. The intermediate die shapes are very important in multi-pass tube shape drawing. In the current paper, the design method for the intermediate dies in a tube shape drawing process is developed using a die offset for corner filling (DOCF) method. Underfill defects are related to the radial velocity distribution of each divided section in the deformation zone. The developed intermediate die shape design was applied to the two-pass tube shape drawing with fixed mandrel for manufacturing a hollow linear motion (LM) guide rail. The proposed design method led to uniform and steady metal flow at each divided section. FE-simulations and experiments were conducted to validate the effectiveness of the proposed method in multi-pass tube shape drawing process.
https://doi.org/10.5228/KSTP.24.5.340 인용 PDF KSCI KPUBS HTML

Shim, J.W.;Shin, J.K.;Park, G.J.
- Proceedings of the KSME Conference
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- 2001.06c
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- pp.531-536
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- 2001
The structural shape optimization is a useful tool for engineers to determine the shape of a structure. During the optimization process, relocations of nodes happen successively. However, excessive movement of nodes often results in the mesh distortion and eventually deteriorates the accuracy of the optimum solution. To overcome this problem, an efficient method for the shape optimization has been developed. The method starts from the design domain which is large enough to hold the possible shape of the structure. The design domain has pre-defined uniform fine meshes. At every cycle, the method judges whether all the elements are inside of the structure or not. Elements inside of the structure are assigned with real material properties, however elements outside of the structure are assigned with nearly zero values. The performance of the method is evaluated through various examples.
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Park, J.H.;Seo, J.Y.;Seol, J.Y.;Hwang, W.S.;Lee, K.H.;Kim, J.Y.
- Transactions of Materials Processing
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- v.27 no.2
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- pp.81-86
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- 2018
In the cold forming process, it is not easy to fabricate a asymmetric type nut, due to the difficulty in the exact prediction of metal-flow. As we have identified, in that case, it often results in the various forging defects such as burrs, and an incomplete shape, as well as other problems because of this issue. In the current study, we introduce the development of an unparalleled shape Weld Nut by using a forging analysis tool (AFDEX). For the multi-forming machine, the optimized shapes of each intermediate product (step product) could be found by the use of a model for the prediction and analysis of various types, sizes and heights. Chiefly, forging tools were prepared based on the simulation results and an unparalleled shape could be prepared at one time without any burrs, incomplete shape and size.
https://doi.org/10.5228/KSTP2018.27.2.81 인용 PDF KSCI

Kang K.G.J.;Park H.J.;Yun J.C.;Kim J.;Kang B.S.
- Proceedings of the Korean Society for Technology of Plasticity Conference
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- 2004.05a
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- pp.87-90
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- 2004
In this paper, net-shape forming of an automobile gear is investigated. Barrel, a component of automobile start motor, is adopted as a net-shape forming. In order to accomplish the goal of net-shape forming without cutting of tooth and cam after forming, forming ability is raised through billet treatment and die design. As a technique of billet treatment spheroidizing annealing of billet to get low hardness and molybdenum disulphide coating to get low contact friction between billet and die is carried out. One of critical points of die design, fillet radii variation of tooth of die is applied to get smooth surface of barrel after cold forging. As a measurement of tooth accuracy, distance between two pins and lead-tooth alignments are investigated. Cam profile accuracy is checked with a 3D measuring instrument. Results obtained from the tests revealed reasonable result with respect to design goal. By these results, the paper shows that reasonable results can be obtained by billet treatment and die design for net-shape forming.
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