SEAR PROCESSING MOLD FOR METAL SHEET, DESIGN METHOD FOR THE SAME, AND SHEARING APPARATUS COMPRISING THE PROCESSING MOLD

摘要

PROBLEM TO BE SOLVED: To obtain a shear processing plane with a high stretch flange property for a shear process of metal sheets by designing a clearance between a punch and a die to be an uneven clearance.SOLUTION: A shear processing mold comprising a punch and a die is characterized in that (i) when a vicinity of a shear processing plane after punching shear processing or piercing processing plane is to be processed by flange-up molding, a clearance between the punch and the die in areas within a distance from a dangerous part of the shear processing plane where stretch flange crack is determined to be most liable to occur according to a simulation, to be 0.5π time of a circular approximation radius of a substantially circular arc shape, an ellipse approximation major axis of a substantially ellipse arc shape, or an ellipse approximation major axis of a substantially ellipse punching shape, in the ridge direction of the shear processing plane, is 1.2-4.0 times of a positive clearance between the punch and the die when the shear processing plane in the dangerous part is to be processed by shearing, and in that (ii) a clearance between the punch and the die continuously and gradually increases from the dangerous part to the 0.5π-time-distance-position in the ridge direction of the shear processing plane.SELECTED DRAWING: Figure 1