| 摘要 |
A piercing nozzle (2) having a nozzle hole (2a) larger than the diameter of a converged laser beam (10) and smaller than the diameter of a hole (1a) of a cutting nozzle (1) is in use. Further, an underlay (3) having a hole (3a) at a position corresponding to the nozzle hole (2a) is placed under the piercing nozzle (2) through a clearance (5). Piercing is carried out by irradiating the laser beam (10) to a machining target (6) through nozzle holes (1a, 2a) and (3a) on condition that a laser oscillator is set to output high power. The diameter of a hole machined by the piercing is small, and less scattered dross is produced. The scattered dross is cooled down within the clearance (5) and is then dropped down to the underlay (3), so that the adhesion of the scattered dross to the machining target does not occur. Since a small hole is machined with the high power, the machining time for piercing is remarkably shortened. |
