• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.434-438
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• 2003

The shearing process for the sheet metal is normally used in the precision elements such as semi-conductor components. In these precision elements, the burr formation brings a bad effect on the system assembly and demands the additional de-burring process. In this paper, we have developed the desktop-type precision punching system to investigate the burr formation mechanism and present kinematically Punch-die auto aligning methodology, for the purpose of burr unifomizing and minimizing, between the rectangular shaped punch and die. By using the scanning electron microscope, the aligned punching results are compared with the miss-aligned ones. Also, we measured the relative burr heights using the self-designed laser measuring device for insitu self aligning. Since it is hard to get the perfect, so called, burr-free edges during the shearing process, we introduced the ultrasonic do-burring machine. The de-burring operation was carried out by a novel do-burring method, the reversal flow resistance method, under different machining loads and abrasive types. The final do-burring results show the validity of our punching do-burring system pursuing the burr-free punched elements.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.03a
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• pp.218-222
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• 1994

The chassis of T.V, cassette, radio and telephone are made up thin-iron plates that makes a lot of female screws to assemble various parts. Then makes hole in the iron plate and forming female screws of burring face after the burring. Female screws forming in thin-iron plate is very difficult working then rolled forming process use of plastic deformation instead of cut forming. In this study goals are solve the trouble problem of industrial field and develop new model tap for prevent chips.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.107-108
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• 2009

This study is focused on the thickness change in burring with stainless 409L according to the change of main design variables and forming conditions, to manufacture the automobile exhaust flange. Large plastic deformations by burring process decreases thickness of inner radius and occurs cracks. The optimal design of performs by the finite element analysis achieves adequate improvement of thickness decrease.

• Transactions of Materials Processing
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• v.30 no.6
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• pp.291-300
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• 2021

Currently, starting with electric vehicles, the application of ultra-high-strength steel sheets and light metals has expanded to improve mileage by reducing vehicle weight. At a time when internal combustion engine vehicles are rapidly changing to electric vehicles, the application of ultra-high-strength steel is expanding to satisfy both weight reductions and the performance safety of the chassis parts. There is an urgent need to improve the quality of parts without defects. It is particularly difficult to estimate the part formability through the finite element method (FEM) in the burring operation, so product design has been based on the hole expansion ratio (HER) and experience. In this study, design of experiment (DOE), analysis of variance (ANOVA), and regression analysis were combined to optimize the formability by adjusting the process variables affecting the burring formability of ultra-high-strength steel parts. The optimal variables were derived by analyzing the influence of variables and the correlation between the variables through FE analysis. Finally, the optimized process parameters were verified by comparing experiment with simulation. As for the main influence of each process variable, the initial hole diameter of the piercing process and the shape height of the preforming process had the greatest effects on burring formability, while the effect of a lower round of punching in the burring process was the least. Moreover, as the diameter of the initial hole increased, the thickness reduction rate in the burring part decreased, and the final burring height increased as the shape height during preforming increased.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.5
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• pp.578-584
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• 2011

In mechanical cutting process, burr was generated at workpiece by cutting tool generally. It is working disturbance during manufacturing process. Besides burr was taken shape relatively large size more micro scale machining than macro scale machining. Many researches have been studied to remove micro burr(de-burring), because it was negative effect for accuracy of machining shape. However, micro de-burring was constrained by burr height, micro feature and so on. In this paper, experimental research was carried out to compare de-burring characteristics of $Al_2O_3$ abrasive and polymer.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.283-284
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.353-354
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• 2010

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4111-4116
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• 2013

The progressive die producing continuously while transferring in order a multiple process is processing law that it is efficient and quality is excellent. In this study the position of precision secured that it occurred when be welded exhaust efficiency of gas boiler combustion exhaust pipe and the exhaust pipe which is cause of incomplete combustion for the purpose of productivity increase. it add burring to a product form and progressive die make die don't disassemble and it be able to exchange burring punch the position of precision and productivity by progressive die is able to improve.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.14 no.1
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• pp.2-8
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• 2006

Numerical analysis of the flow field in the reactive medium of End-Burring combustor is studied in order to investigate the combustion characteristics of hybrid combustion. The main part of this study is focused on the port diameter effects of oxidizer injector on the temperature distribution within the reactive field. It is found that the case having the largest port diameter(25 mm) delivers the optimum conditions for the design of End-Burring combustor where the predicted temperature field showed the most acceptable distribution.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.04a
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• pp.151-154
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• 2000

The yoke is used for joining the mechanical element of a spider and shaft in the steering system of automobiles. Conventional yoke forming processes are too complicated such as 4 stages bending and forming. The weight of yoke is also heavy than other components. New process is necessary to reduce the product weight to improve the strength and to reduce the costs. Process designed to reduce number of forming stages and to reduce its weight. To check the strength the stress analyses are performed between conventional yoke and developed one.