Investigation of laser percussion hole drilling by use of speckle correlation.
In this paper speckle correlation is introduced as a tool to investigate the heat-influenced area during material processing with laser light. Two materials were investigated, a pure silver sheet and a sheet of SiC-diamond composite. The processing laser used in the experiments was a diode-pumped acousto-optical Q-switched Nd:YAG laser that allowed percussion hole drilling to be performed using green light through a second-harmonic crystal. The measurements were performed using a continuous-wave He-Ne laser and a digital camera. The experimental results show that the heat-influenced area is approximately 5000 times larger than the actual hole being drilled and that it reaches a steady-state condition toward the end of the processing cycle.
Yalukova
O
O
Department of Physics and Mechanical Engineering, Luleå University of Technology, SE-971 87 Luleå, Sweden. yalukova@yahoo.co.uk
Miroshnikova
N
N
Gren
P
P
Sárady
I
I
Sjödahl
M
M