| 摘要 |
PURPOSE:To improve cutting speed by injecting an outer assist gas along an inner assist gas and swirling both gasses for injection. CONSTITUTION:When a material to be cut is irradiated with a laser beam 1 and simultaneously oxygen is supplied to the passage 24 of an inner assist gas, a swirling gas flow f1 is formed by a flow straightening member 26. When oxygen is supplied to the passage 22 of an outer assist gas, a swirling gas flow f2 is formed by a flow straightening member 28. The swirling gas flow f1 prevents the lowering of oxygen purity caused by the atmospheric air taken in and also by combustion gasses and slag mixed in. By the ambient protection through the swirling gas flow f2, the directivity of the swirling flow f1 is protected from being interfered by an external air flow. Consequently, a new assist gas with a high purity is always supplied to the cross-section. |
