JPS55114490A - Laser welding method - Google Patents

Abstract

PURPOSE:To prevent the formation of craters without breaking the thermal stability of the resonator by constituting the focus position of a laser beam movably in the radiation direction and expanding the welding area part of the final end of the weld zone thereby decreasing power density. CONSTITUTION:In welding the welding work 11 on a working table 10 by the laser beam 3 passed through a small barrel 8 through a reflecting mirror 9, the focusing lens 2 of the laser beam 3 is constituted slidably by the mechanism of a holder 4, motor 7 and feed screw 6 and the focus position of the beam 3 is constituted moving-adjustably in the radiation direction by a control unit not illustrated. The radiation part is moved in the arrow direction with respect to the weld zone 12 of the welding work 11 to form a weld zone 14. At the final end of the welding, the focus position is kept apart from the welding work 11 through the movement of the lens 2 to expand the welding area and qaudually decrease the welding density, whereby the beam hold 13 is made shallow and the formation of any crater is prevented. Unlike in conventional methods, the resonator may be held with good thermal stability because this does not involve gradual decrease of the beam output.