Abstract
We investigated a method for reducing work damage in micro-drilling using a Bessel beam of a nanosecondpulsed laser. While work damage (discoloration and concentric circular marks) was clearly visible on irradiated surfaces of SUS304 and copper, this kind of damage was barely visible on those of aluminum. Metals such as SUS304 and copper are easily damaged by pulsed laser irradiation as a result of discoloration due to surface oxidization. By contrast, metals that have transparent oxides are not readily damaged. By irradiating workpieces in a vacuum, oxidation can be avoided and penetration holes can be produced using a lower irradiation pulse energy density.
