| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and a device for enabling high speed transfer of a raw material and high-speed press processing by enlarging a clearance on a bottom punching stage and loosening accuracy of work positioning while a coaxial accuracy of a center hole and a work contour shape is remained at high accuracy. SOLUTION: A taper part 25 is formed to chamfer a tip part of a top punch processing punch 3, and also a taper part 26 is formed at a tip part of a die hole 13a in a die 13 on the opposite side, so that a zero or positive clearance C is provided between them. When top punching is performed, a shearing face 51a on a coil material 51 side and a shearing face 28 of a work W are formed into a tapered shape respectively, so as to minimize as much as possible an overlapped volume a of the disc-like work W and the coil material 51 which have to be cleared at the time of bottom punching.
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