| 摘要 |
PURPOSE:To promote a laser beam cutting process as assistant gas holds its purity without being hindered by excessive air by selecting the ratio of an inner diameter of a nozzle point to an outer diameter thereof at a specified value. CONSTITUTION:The value of a ratio of an inner diameter d1 of the nozzle 3 to an outer diameter d2 thereof is selected to be >=3. The outer diameter d2 of the nozzle 3 is larger than the inner diameter d1, and at a cutting time, the nozzle 3 is enclosed by a wide surface and faces a work piece 5 through a narrow clearance like a thin sheet. Accordingly, the assistant gas 4 supplied along the laser beam 1 is spouted from the nozzle 3 and ejected at a high speed as the speed of flow is accelerated by a narrow clearance. In this case, since the neighborhood of the cut part of the work 5 is shielded by a narrow clearance in the shape of a thin sheet, the work 5 is fused, vaporized and cut in an instant by the laser beam 1 fitted perfectly to the optical axis. Cutting efficiency is prevented from being deteriorated by dilution, etc., of gas purity based on mixture of the air and the deposit of dross is minimized because the assistant gas is used effectively. |
