| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for punching by suppressing the occurrence of a cutting scum or burr in the case of batch punching a plurality of holes and easily removing the generated scum or the burr. SOLUTION: The method for punching a plurality of holes comprises the steps of coating a pipe 1 of a material to be worked on a support pole 12, and punching the plurality of the holes at the side face of the pipe 1. The method further comprises the steps of arranging punch units 14, 18 having first punches 17a, 21a, second punches 17b, 21b and third punches 17c, 21c so as to interpose the pole 12 between the punch units 14 and 18, punching the plurality of the holes with a deviation of a slight time when the punch units 14, 18 are moved toward the pole 12 mounting the pipe 1, and removing the generated scrum 31 to the cavity 8 in the pole 12.
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