| 摘要 |
PURPOSE:To enable the effective design of a die by finding with experimentally obtd. computation expression the curvature of the curving part by the springback of the material of a forming item after pressing. CONSTITUTION:A forming item 9 is formed by the upper die 4 and lower die 2 and composed of a curving part 10 and peripheral edge part 11. In drawing the peripheral edge part 11 is pinched between a blank holder 5 and the lower face side of the outer peripheral part of the upper die 4 and engaging grooves 7, 7' and projecting bars 8, 8' ensure the drawing by the lower die 2 and upper die 4 with mutual cooperation. The computation expression of eta=1-rho/rho' is obtd. with eta springback factor, rho radius of curvature of the center face of the steel plate and rho' radius of curvature for that after springback. The design of the rho' estimating the variation in the curvature of the curving part is performed according to this eta. In this way the shape of the die can be set reasonably and the die for drawing can be formed effectively.
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