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鄭準基 弘益大學校 科學技術硏究所 2005 科學技術硏究論文集 Vol.16 No.-
In deep drawing of sheet metal, there are many cases in which the uniform and thin wall thickness of the drawn products is more important than the bottom thickness. In this case, we can not easily get the deep drawn products with the uniform and precise wall thickness by only drawing process. Therefore in general the manufacturing processes which both the drawing and the ironing process are proceeded sequentially are used. But this method has the disadvantages of a cost-up, decrease of productivity and degradation of quality, because the ironing process is added after the drawing process. In this study, in order to improve those problems and to enhance the effect of deep drawing, the combined process of redrawing and ironing for multistep drawing of cylindrical cups is used. In this experiment, we considered the characteristics of the combined process such as the relation between the drawing and ironing rates, the drawing limits and the forces needed for operations. The suggested force prediction shows that it can successfully represent experimental results.
鄭準基 弘益大學校 1982 弘大論叢 Vol.14 No.2
The cutting forces on obique cutting with single cutting edge are investigated analytically, based on the thin shear zone model. To predict the three components of oblique cutting forces analytically, an experimental data of orthogonal cutting and cutting energy method are used. And the predicted results are in good agreement with the experimental results under the equivalent cutting conditions. The results obtained in this study are summerized as follows, 1.The cutting forces of the oblique cutting can be predicted analytically by applying energy method even if only orthogonal cutting data are in hand. 2.The analytical prediction of cutting forces on oblique cutting with single cutting edge is applicable to the double cutting edge model.
鄭準基 弘益大學校 科學技術硏究所 1999 科學技術硏究論文集 Vol.10 No.1
Milling operations with endmill are performed to investigate the characteristics of laser beam signals due to tool deflection and fracture. The laser beam signals are obtained with adapt focusing of tool. Tool conditions are identified with scanning electron microscopy and optical microscopy. It is demonstrated that the laser beam signals provide reliable informations about the cutting processes and tool conditions. Moreover, tool fracture can be detected successfully using the coefficient of variation.