LASER BEAM CUTTING METHOD AND LASER BEAM CUTTING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a laser beam cutting method for a steel plate and its device which realize laser beam cutting having excellent quality in a cut face by solving problems such as roughness on the cut face, reduction in vertical streak pitch, and adhesion of dross in the laser beam cutting. SOLUTION: In this method wherein a steel plate 1 is heated and melted by irradiating the steel plate 1 with a laser beam 4, and the steel plate 1 is brought into the laser beam cutting by shifting a laser beam irradiation part along a cut line, a plurality of, two or more condensing spots 8 of the laser beam are arranged side by side in a direction perpendicular to a cutting and traveling direction on the steel plate 1, and the steel plate 1 is cut.