PUNCHING MACHINE AND METHOD FOR METAL SHEET WITH INVERSELY TAPERED PUNCH AND CHAMFERED DIE

摘要

PROBLEM TO BE SOLVED: To provide a punching machine and method by which burrs on a punched end face are reduced.;SOLUTION: The punching machine has a punch 8, a die 11 and a blank holder 10. The punch 8 has a first parallel part 29 having the same cross-sectional shape including a blade edge and an inversely tapered part 9 the outside diameter of which is made smaller toward the rear in the direction of punching from the first parallel part 29. The blade edge of the die 11 is inclined in the direction of punching and is chamfered. The blank holder 10 has a hollow part 31 which is similar to the blanking part 30 of the die 11 and the inner circumference (c) of the hollow part 31 is equal to or larger than the outer circumference (a) of the first parallel part 29 of the punch 8 and is equal to or smaller than the inner circumference (b) of the blanking part 30 of the die 11.;COPYRIGHT: (C)2010,JPO&INPIT