| 摘要 |
PROBLEM TO BE SOLVED: To provide a pinch trim punch capable trimming without generating a burr. SOLUTION: At a place facing a cutting edge part 3a of a pinch trim punch 3 in a material 1 to be worked, a recessed groove 6 is formed along a profile shape to be trimmed directing upward roughly in an opposite direction for the punching direction of a pinch trim die 4. Next, pinch trimming is done to separate the material 1 and a scrap 2. By this method, the distance from the bottom part of the recessed groove 6 to the cutting edge part 4a of the pinch trim die 4 is made a minimum distance in punching, a shear stress is concentrated at its portion, as a result, a crack 7 is generated from the bottom part of the recessed groove 6, a burr is not generated in a cut part completely.
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