| 摘要 |
PURPOSE:To prevent the sticking of the shear droop and foreign matter produced in the stage of melt cutting and to improve the quality of the resultant joint part in the stage of melt-cutting the ends of metallic strips with a laser beam by melt-cutting the ends while injecting gas to the bottom end of the melt-cutting part. CONSTITUTION:The preceding strip 1 and the succeeding strip 1' are clamped by upper and lower clamps 3, 4, 3', 4' and are melt-cut in the clamped state while the laser beam 2a is irradiated thereon by moving discretely a laser welding torch 2. The gas 8 is injected to at least the bottom end part in the melt-cut end faces 1a and 1a' of the sheet 1 and the sheet 1'. Gaseous O2, high- pressure air, etc. suffice when the removal of the shear droop, etc. during laser welding is intended. H2 or a gaseous mixture composed thereof is used when the cooling of the bottom end is intended. The respective melt-cut end faces are thus maintained in the perpendicular or nearly perpendicular state and therefore the joining with high accuracy is made possible. |
