| 摘要 |
PROBLEM TO BE SOLVED: To provide a method capable of easily judging that a fine pore is penetrated upon the boring according to laser processing to a cavity part disposed on the interior of a metallic member.SOLUTION: In a penetration method, a fine pore having an inner diameter of 30 to 1000 μm extended in the direction of intersecting one direction with respect to a cavity part disposed so as to be extended to the one direction from an edge surface of a metallic member to an inner part thereof as when communicating a gas release hole with a gas introduction path of an outer cylindrical part of a gas release metal roll is penetrated from an outer surface of the metallic member. Therein, laser working is performed while a rod 30 made of fluorine resin is inserted from an opening part on the edge surface of the cavity part, thereafter, a laser mark 32 of the rod 30 is investigated and, thereby, the penetration of the fine pore is determined. |
