Abstract
We investigated a method for reducing work damage in micro-drilling of metals (SUS304, copper, titanium, and aluminum) using a nano-second pulsed Bessel laser beam. Work damage (discoloration and concentric circular marks) due to the side lobs of the Bessel beam are seen on the irradiated surface of SUS304 and copper. On the other hand, in aluminum and titanium, there is little discoloration area on sample surface. In the cases of SUS304 and copper, the absorptivity increases as a result of discoloration due to surface oxidization, and damage is generated. In contrast, for the case of aluminum and titanium, even if the oxide is formed on the surface, neither discoloration nor the changes in absorptivity are remarkable.
