Study on aerodynamic nozzle specialized for laser welding

In this paper,an aerodynamic nozzle was investigated for protecting the beam deliveray system and preventing optics pollution from ejected particle vaporized on metallic surface during high power CO2 laser welding. The suitable nozzle structure was designed on the basis of theoeretical analysis on moving trajectory of the ejected particle. The comparing experiments between aerodynamic nozzle and ordinary nozzle were performed to examine the influence of optics pollution on loss of laser power,porosity percentage of weld section; and efficient penetration depth,and also to inspect the distrubution of ejected particle on optics during laser welding. The studied results show that the aerodynamic nazzle substantially reduced the particle amount on the optics,so the loss of the laser power delivered to the workpiece was reduced,the effective weld lentgh was increased.The examination of the weld structure ensured that there was no interference with the quality of the weld due to the cross flow.