Selection of Semi-angle and Analysis of Inhomogeneous Deformation for Skin-pass Drawing ofRectangular Shapes

• Main Authors: Chi-Yi Tseng, 曾竹毅
• Other Authors: Heng-Sheng Lin
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/wsmveg

碩士 === 國立虎尾科技大學 === 機械與機電工程研究所 === 96 === Transmission components used in precision machines like rails or sliders for linear motion guide demand high straightness and shape precision. The precision of these components affect the precision of machine movement and subsequent machining or measuring precision. Prior to machining, workpiece for the rails or sliders has to be rolled or drawn. Cold skin-pass drawing is usually applied on the preform, which may be produced by multiple shape rolling or drawing, with light reduction of cross-section. The cross-section of the shaped workpiece can be considered to be comprised of rectangles. As for drawing with rectangles, there can be possible combinations of different thickness and die semi-angle along both the width and thickness directions. It would require tremendous amount of case simulation in searching of the optimum die semi-angle by Taguchi method. In order to verify the guideline in selecting the optimum die semi-angles, this work first computed the drawing load of square bar by finite element simulation with DEFORM-3D under various combinations of die semi-angles and reduction of cross-section. Optimum angle can be obtained which yielded lowest drawing load for the same reduction. “Mean variation of effective strain” was defined in order to quantify the level of deformation inhomogeneity under the choice of various parameter combinations. The result of square drawing was further applied to the selection of optimum die semi-angles for drawing from rectangle to square, and corresponding deformation inhomogeneity was also verified with finite element simulation. The finite element simulations verified that when drawing square to rectangle with different width and thickness reductions, the range of optimum die semi-angle in the width direction fell between the optimum angles in drawing square with the same width reduction and with same area reduction. While the range of optimum die semi-angle in the thickness direction fell between the optimum angles in drawing square with the same area reduction and with the same thickness reduction. The corresponding deformation inhomogeneity also fell in the range as predicted by this guideline.