| 摘要 |
PURPOSE:To prevent rise of a slug and to perform smooth punching in punching using a punch and a die by making the depth of the vertical circumferential face in the punch hole of the die specific times the thickness of a blank and forming the lower part thereof into a divergent tapered hole. CONSTITUTION:The depth (h) of the vertical circumferential face 7 in the punch hole 5 of a die 3 is made 0.25-0.4 times the thickness T of a blank material P and the lower part 8 thereof is formed into a downward divergent tapered hole 8. The periphery (a) of the slug 10 blanked by a punch 2 is bulged by the residual stress in the tapered part 8 and is prevented from being removed upward even if the punch 2 rises. The punching is thus smoothly accomplished. |
