Highspeed Laser Micro Processing using Ultrashort Laser Pulses

Abstract

This paper discusses results obtained in highspeed laser micro processing of zirconium oxide ceramic and stainless steel. High-PRF (pulse repetition frequency) femtosecond laser systems were joined together with fast galvanometer scanner systems. A high average laser power (31.7 W) and fast scan speeds (17.1 m/s) were applied in order to increase material removal. The influence of average laser power, laser energy and repetition rate on both the volume ablation rate and the machining quality was studied. The maximum volume ablation rate for zirconium oxide was 70.3 µm³ per pulse, obtained with pulses of 5.9 µJ energy and 1.02 MHz. It is demonstrated that material removal on zirconium oxide will be strongly affected by heat. Stainless steel was irradiated with a maximum laser power of 31.7 W and various repetition rates. The maximum material removal rate was found to be 6.8 mm³ / min, achieved with laser pulses of 0.85 J/cm² fluence. The feasibility of the highspeed laser technology in micro processing is verified by machining examples. In addition, a demonstrator of 80 x 80 mm² was machined with a processing rate as high as 25 cm² / min.