| 摘要 |
PURPOSE:To obtain a good cut surface having excellent smoothness by concentrically blowing an assist gas at and under a sufficiently high flow velocity and high dynamic pressure to the molten part of the cutting part and hardly generating the disorder of the flow of the assist gas. CONSTITUTION:A nozzle front end face 5 facing the front surface of a member W to be cut is provided in contact therewith or apart a slight spacing therefrom. A laser beam irradiation hole 11 is opened at this nozzle front end face 5 and an assist gas ejection port 15 is opened at the nozzle front end face 5. The opening shape of this assist gas ejection port 15 is formed to a slit shape meeting the cutting shape. |
