| 摘要 |
PURPOSE:To raise a spatter preventing effect, and to extend the life of a lens by attaching a tapered cone-shaped hood to the tip of a condensing lens, and providing main and sub-assist gas jet ports in the vicinity of its upper end and in the tangential direction along the side face of the hood. CONSTITUTION:A tapered cone-shaped hood 4 is attached to the tip part of a condenser lens 3 of laser beams 2. Also, main and sub-inert assist gas jet ports 10, 12 are provided in the vicinity of the upper end of this hood 4, and in the tangential direction along the side face of the hood 4. The main assist gas which has been jetted out of the jet port 10 flows vortically along the inner surface of the hood 4, energized by the sub-assist gas and jetted out of an opening 6. Accordingly, a spatter which has been generated by beam welding is swallowed up by this vortex and discharged, scarcely reaches the condenser lens 3, and the life of the lens is extended. In this regard, the sub-assist gas jet port 12 can be provided in several places, and it is also allowed that the vortex gas is discharged by providing a spiral-shaped groove 8 on the inner surface of the hood 4. |
