| 摘要 |
PROBLEM TO BE SOLVED: To provide a punching method by which the occurrence of enamel hairs is suppressed even when a sheet to be worked is a coated steel sheet having comparatively thick coating film when punching work is applied to the coated steel sheet. SOLUTION: A flat coated steel sheet to be worked is punched into a desired shape by using a punching die with a punch and a die; then a punched product is deformed into a bent shape between the punch and the die in the state where the punch and the die are held in the punching-finished position; and the punched product is returned to the original flat state by spacing the punch and the die in the state before punching in the state as holding the product into the bent shape. COPYRIGHT: (C)2011,JPO&INPIT
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