| 摘要 |
PROBLEM TO BE SOLVED: To effect laser cutting which has a high absorptivity of laser energy of an object to be machined, without imparting special property to it, by first emitting a groove-forming laser beam to a cutting part to form the groove, and then irradiating the groove with a cutting laser beam. SOLUTION: For a cutting laser 5, a continuous wave CO2 laser is used having 5-25kW output for example while, for a groove forming laser 7, a CO2 laser is used having the peak output of 10-50kW for example. These laser beams are converged on the surface of the cutting part of a steel plate 1, with the laser irradiation position moved along the cutting line by a driving means for moving a machining head or an object to be machined. In this case, the moving speed is desirably 1-100 m/min for the steel plate at the laser irradiation position. While an assist gas is supplied using an assist gas nozzle 9, the gas desirably has O2 gas as the main component. |
