METHOD OF FORMING THROUGH-HOLE IN CIRCULAR WALL OF WORK PIECE AND MACHINE FOR FORMING THROUGH-HOLE

摘要

PROBLEM TO BE SOLVED: To provide a method of forming a through-hole in a circular wall of a work piece capable of preventing formation of burrs in a inner peripheral wall of a tubular part, improving machining efficiency and reducing machining cost, and to provide a through-hole forming machine.;SOLUTION: The method comprises setting the work piece 10 to a die 20, inserting a punch 30, which is provided to a rod-shaped metal core 32 held in cantilever, into an inner side of the tubular part 12 in the state of opposing to the inner wall surface of a portion to be bored with the through-hole 70, relatively pressing and moving the punch 30 via the metal core 32 between itself and the die 20 toward the direction where punching is performed, and simultaneously pressing and moving a press pin 35 inserted into the work piece 10 so as to abut on a surface 33 opposite to the surface of the metal core provided with the punch 30 from a through-hole 72 for work disposed in a portion in the side opposite to the circular wall portion to be opened the through-hole 70 of the work piece 10, together with the metal core 32 and the punch 30, thereby driving the punch 30 from the inner side of the tubular portion 12 into the circular wall 15 and drilling the through-hole 70.;COPYRIGHT: (C)2006,JPO&NCIPI