• Journal of the Korean Society for Precision Engineering
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• v.28 no.3
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• pp.301-307
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• 2011

In this paper, effects of major design parameters of cold forging dies on die mechanics are quantitatively investigated with emphasis on shrink fit using a thermoelastic finite element method. A ball-stud cold forging process found in a cold forging company is selected as a test process and the effects of die insert material, magnitude of shrink fit, dimension of shrink ring, number of shrink rings, partition of die insert and clamping force on effective stress and circumferential stress are analyzed. It has shown that the number of shrink rings, magnitude of shrink fit, and Young's modulus of die insert material have strong influence on compressive circumferential stress in die insert but that the influence of the other design parameters is relatively weak.

• Progress in Superconductivity and Cryogenics
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• v.9 no.1
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• pp.14-17
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• 2007

The slot-die coating & calcination process was adopted to fabricate the long YBCO precursor films on the buffered metal tape for the $2^{nd}$ generation coated conductors. To obtain the smooth and crack-free surface of long YBCO precursor films, the parameters of slot-die coating and the process variables of calcination step must be optimized simultaneously in reel-to-reel method. Among the parameter of slot-die coating process, the viscosities of the precursor solution was controlled from 60cP to 200cP to obtain the thicker films from on single coating. The slot-die gap, the injection rate of precursor solution, the moving speed of buffered metal tape etc. are controlled lot the full coverage and smooth surface of YBCO precursor films. The slot-die coated films are moved through the tube furnace with predetermined heating profiles in humid oxygen ambient The YBCO precursor films was identifed with $Y_2O_3,\;BaF_2$, and CuO phase by XRD and consisted of fine grains of about 20nm size observed by FE-SEM. The YBCO films show the critical current density over $MA/cm^2$ using the precursor films formed by the continuous slot-die coating & calcination process.

• Design & Manufacturing
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• v.9 no.3
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• pp.41-44
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• 2015

The progressive die is processing methods that can improve the productivity for sequentially transferring while continuously producing in multiple processes. In this study was carried out the die analysis through the load analysis acting on the terminal die and sheet metal forming also the study was carried out with respect to optimized die design for the terminal die and progressive die manufacturing using the CimatronE Die Design.

• Transactions of the Korean Society of Mechanical Engineers
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• v.8 no.1
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• pp.57-64
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• 1984

Forward extrusion of sintered porous metal through conical converging die is analyzed using slab method on the basis of plasticity theory for porous metal. It is taken into consideration in the analysis that the material in the container is continuously recompressed on densified until the process reaches steady state. Extrusion pressure and distribution of relative density from the die inlet to the outlet are calculated under various process variables. The results are useful in finding initial relative density of the billet, reduction of area and cone angle of the die in order to get required final products. Experiments are done for porous copper and then compared with the computed results.

• Transactions of Materials Processing
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• v.9 no.3
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• pp.284-292
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• 2000

Optimization of the process parameters is carried out for process design in sheet metal forming processes. The scheme incorporates with a rigid-plastic finite element method for the deformation analysis and response surface methodology for the optimum searching of process parameters. The algorithm developed is applied to design of the draw bead force and the die radius in deep drawing processes of rectangular cups. The present algorithm shows the capability of designing process parameters which enable the prevention of the weak part of fracture during processes.

• Journal of Korea Foundry Society
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• v.24 no.6
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• pp.347-355
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• 2004

In the die casting process, the flow of liquid metal has significant influence on the quality of casting products and die life. For the optimal process design of automobile gear housing, various analyses were performed in this study by using computer simulation code, MAGMAsoft. The simulation has been focused on the molten metal behaviors during the mold filling and solidification stages for the sound casting products. Also the internal defects were predicted by application of air pressure and feeding criteria.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.316-319
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• 2008

The L-bending of inner-structure bonded sandwich sheet metal is examined by using a bending die attached to the material testing machine. The specimen is composed of top and bottom layers and a middle layer of pyramid-core structure and each layer is bonded by brazing. The variables chosen for experiments were clearance between punch and die, location of bend line on the specimen surface and clamping type of specimen during L-bending. Effects of these variables on deformation of specimen around die-corner radius were investigated. It was shown that the irregular shapes of recess are formed in the inner layer of bended parts and they greatly depend on working conditions.

• Korean Journal of Optics and Photonics
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• v.24 no.6
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• pp.342-346
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• 2013

We present the thermal analysis result of die bonding for a high power LED package using a metal hybrid silicone adhesive structure. The simulation structure consists of an LED chip, silicone die adhesive, package substrate, silicone-phosphor encapsulation, Al PCB and a heat-sink. As a result, we demonstrate that the heat generated from the chip is easily dissipated through the metal structure. The thermal resistance of the metal hybrid structure was 1.662 K/W. And the thermal resistance of the total package was 5.91 K/W. This result is comparable to the thermal resistance of a eutectic bonded LED package.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.05a
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• pp.86-91
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• 2002

The production part requiring multiple processes such as piecing, blanking and notching, are performed with a high production rates in progressive die. In order to prevent the dejects of process result, the optimum of strip process layout design, die design, die making, and tryout with inspection etc. are needed. According to these factors of die development process, they required theory and practice of metal working process and its phenomena, die structure, machining conditions for die making, die materials, heat treatment of die camponents, know-how and so on. In this study, we designed and analyzed die camponents also simulated the strip process layout of multiple stage drawing by DEFORM. Especially the result of tryout and its analysis become to the feature of this study.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.76-79
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• 1999

The study has been performed for the relation between die and product in forward extrusion by the experiment. Strains of the die have been given by the simple experiment using the strain gauge located at the outer surface of the die and the history of the deformation of the die and product is given by the experiment and Lame's formula. The inner pressure of the die causes the deformation of die that affects the accuracy of dimension and shape of product. The product with accurate dimension and shape can be obtained by analysing elastic deformation of the die during process. The deformation of the die during metal forming process has been usually predicted by the experience of industrial engineer or finite element analysis. But it is difficult to predict the dimension of product at unloading and ejected states. The study has given useful results for the deformation history of the die and product through the experiment and Lame's formula at forward extrusion for solid cylinder and can be applied to the die design for product with accurate dimension.