WELDING CHARACTERISTICS WITH 3 ND-YAG LASER-BEAMS TRANSMITTED THROUGHSINGLE OPTICAL-FIBER

A YAG laser processing system in which three YAG laser beams were comb ined on the input end of a single optical fiber, and transmitted throu gh the optical fiber, was developed, The effects of various oscillatio n wave forms on the penetration depth were examined by using this syst em. As a result, it was confirmed that the penetration depth with a re ctangular modulated laser beam was deeper than that of a continuous la ser beam, and the depth made with the rectangular modulated laser beam superimposed pulse laser beam was deeper than that of the former two type laser beams, though the average output powers of the three types of laser beams were equal to each other. The effective delay time of t he pulse laser beam after rising of the rectangular modulated laser be am was 2 or 3 ms to obtain the deepest penetration, Moreover, the pene tration depth increased with an increase in the pulse laser beam power to the total one. (C) 1998 Laser Institute of America.