PURPOSE: To enable the hardening and welding by laser beam by making the laser beam reflecting mirror in the laser beam machine using a single mode laser beam a reflection face of specific radius of curvature.
CONSTITUTION: In the laser beam machine of the single made beam of which beam diameter is small and the divergent angle is small, widely used in general and aiming for cutting, when a laser beam L is converged by a condensing lens 5 and reflected by two reflecting mirrors 9, 10 to harden or weld the metal material P to be processed, the reflection face 9a of the reflecting mirror 9 is made a plane, a spherical recessed face reflection part 10b is provided at the center of the reflection face 10a of the reflecting mirror 10 and the reflection face 10c at the outside thereof is made a plane reflecting part. Since the laser beam L projects by the face having diffused extension the surface of the metal material P to be processed, the laser beam strength is not so strong as at the cutting time, attained to the strength to the extent optimum for hardening and welding and the hardening and welding by the laser beam are easily effected by the laser beam machine of a single beam mode with cutting as the main purpose.
MARUYAMA IWAO
KUWABARA TAKASHI
