Laser beam machining apparatus and corresponding method which employs a laser beam to pretreat and machine a workpiece

摘要

A laser beam machining is carried out by irradiating beforehand the laser beam along a final locus for a main machining, under such a condition as to obtain an energy density for removing a galvanized layer as a surface substance of a work. Thereafter, the laser beam is irradiated to a bare area on which the zinc has been removed, while changing only the energy density according to a cutting condition to cut the work.