| 摘要 |
An object of the present invention is to provide a punching method using a punch, which makes it possible to effectively improve the durability of a tooth portion of the punch. In a punching method using a punch for forming a through-hole in a workpiece by punching the workpiece using a punch, at least a tooth portion of the punch is made substantially solid when the workpiece is punched by the punch, and the tooth portion is made substantially hollow, thereby a diameter of the tooth portion is reduced by a reaction force received from the workpiece, when the workpiece is separated from the punch after the punching of the workpiece.
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