| 摘要 |
<p>Laser apparatus includes a laser and optical means 13 for directing an output beam 22 of the laser through a first nozzle 20 onto a workpiece 14. The nozzle has an aperture through which the laser output beam and a first stream of gas may pass. A second nozzle 24 is provided, coaxial with and surrounding the first nozzle and having an aperture 25 through which a second stream of gas may pass. Gas control means are provided to determine the rate of flow and nature of the gas flowing through each nozzle. <IMAGE></p> |
