| 摘要 |
PROBLEM TO BE SOLVED: To provide a punching method by which scrap-rising is prevented inexpensively and surely in the punching of a flat metal sheet.SOLUTION: This punching method includes: a projection forming stage where a projection part 1a curved in the shearing direction is formed in a region where is held between a die 2 and a stripper plate 3 and weighted in the shearing direction in the peripheral part of a part 1c to be punched of the flat metal sheet 1; a holding stage where the circumference of a part 1c to be punched is held with the die 2 and the stripper plate 3 and a punching stage where the part 1c to be punched is punched with a punch 5, the part 1c to be punched is separated from the flat metal sheet 1 as a punched scrap and a hole is opened on the flat metal sheet 1 by pushing out the part into a die hole 2a. In this punching method, when performing punching with the punch 5 in the punching stage, by imparting compressive weight to the projecting part 1a beforehand when performing a holding stage, the part 1c to be punched is made into the state where the weight is imparted in a direction along the surface and back faces of the flat metal sheet. |
