Laser cutting method

摘要

A laser cutting method that offers a practically acceptable smooth cut surface without lowering the cutting speed. In this method, a laser beam machining device having a variable-curvature mirror assembly is used. The mirror assembly includes a mirror plate having a convex back side and a front reflecting surface, and a piezo-actuator for deforming the mirror plate to change the curvature of the reflecting surface. A laser beam is produced from the device so as to be reflected by the reflecting surface of the mirror plate and condensed at a focal point. The piezo-actuator is actuated to change the curvature of the reflecting surface, thereby oscillating the focal point along the optical axis of the laser beam at a frequency of between 150 Hz and 300 Hz and an amplitude of between+/- 0.5 mm and +/- 3 mm.