Ablation Mechanisms of Double Nanosecond Pulses Laser Drilling

Thirty nanosecond 1.064 μm laser pulses separated by 150 nanoseconds have been shown up to ten times material removal rates while minimizing redeposition and heat-affected zones. The diameter of hole entrance is approximately 450 μm and half hole taper angle is 12 degree. The internal wall of the hole is bright black, no recast layer, no microcrack, smooth and no burr. The laser bursts drilling model is put forward and instantaneous process of laser drilling is discussed.