PUNCHING METHOD OF HOLE HAVING EXTRA SMALL DIAMETER

摘要

PURPOSE:To punch a hole to have a homogeneous inside surface layer and to obtain the satisfactory fine hole by combining punching using a heat source having a high energy density and diffusion penetration treatment. CONSTITUTION:The fine cracks 3 formed on the heat-affected zone 2 on the inside surface of the hole punched in a material which is subjected to punching by the laser light, electron beam or electric discharge machining used as a heat source having a high energy density are subjected to a diffusion penetraton treatment by which the cracks 3 can be fully covered with a film layer 4. The material is subjected to a heat treatment after the diffusion penetration treatment by which the layer 5 is diffused down to the zone 2 and the base part 1. The inside surface of the punched part is thus made homogeneous and the characteristic of the defectless inside surface of the punched hole is obtd.