Preliminary tests on laser milling of zirconium oxide (ZrO2)

The present investigation deals with laser milling process of zirconium oxide (ZrO2), by using a Q-Switched 30 W Yb:YAG fiber laser. The role of laser operational parameters, laser beam scan speed, pulse frequency, the number of times that the machined area is fully scanned (number of repetition), and the scanning strategy, was investigated, allowing to identify the most suitable processing window in terms of surface quality and machined depth. Too low and too high scan speed leads to a darkening of the machined surface. Furthermore, the machined depth increases as the scan speed decreases. Between the strategies adopted, the best result, in terms of machined depth and surface quality, is given by the CROSS strategy. The obtained machined depth linearly depends on the number of repetition; however an increase in number of repetition involves a worsening of surface finish. Finally, high pulse frequency does not guarantee a good surface quality, leading to the formation of dark points on the sample surface.