RIPPLE-OSCILLATED YAG LASER BEAM DEVICE AND EQUIPMENT FOR WELDING THIN STEEL PLATE USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a device with which a ripple-oscillated laser beam is obtained by efficiently coaxially synthesizing a pulse-oscillation YAG laser beam and a continuous-wave oscillation YAG laser beam, and to provide equipment for laser beam welding with which a setting accuracy of a butting gap for preventing the generation of a burn through or a humping in a butt welding of thin steel plates is remarkably relaxed. SOLUTION: Either a YAG laser beam unit which generates a conventional solid laser beam or a YAG laser beam unit which generates a hollow laser beam which has a spatial distribution in reflectivity of a partially transparent mirror is set at a continuous oscillation and the other is set at a pulse oscillation. A ripple waveform is realized at a high efficiency by coaxially synthesizing these laser beams with a beam coupler which has a prescribed aperture. Further, as a ripple condition, the ratio of a mean output of the pulse component to a total output is set at a prescribed value and applied to a butt welding of the thin steel plates.