Velocity and Angle of Spatter in Fine Laser Processing

Scattering velocity and angle of spatter were investigated by recognizing and tracking spatter with the high-speed video observation. The spatter movement was observed by two high-speed video cameras, and analyzed by two- direction tracking method, in which the 3D tracking lines of spatter were constructed in the forward and backward frames and the actual trajectory of individual spatter was obtained by averaging those tracking lines. It made clear that the initial velocity of spatter was less than the speed of sound and mainly ranged from 75m/s to 200m/s. The velocity of spatter showed the slight correlation with the angle.