High-quality processing of CFRP with a 1.1-kW picosecond laser

Carbon fiber-reinforced plastic (CFRP) was processed with a unique ultrafast laser delivering 8-ps pulses and an average output power of up to 1.1 kW at a pulse repetition rate of 300 kHz corresponding to a maximum pulse energy of about 3.7 mJ. Heat accumulation effects become the major issue at such high average powers. In the presented work, heat accumulation resulting from pulse overlap and from repetitive scans was investigated. The results allow estimating both the feed rates necessary to avoid heat accumulation by consecutive pulses and the maximum number of scans allowed avoiding detrimental heat accumulation by the consecutive scans in order to maintain good quality of the processed parts. The capabilities of the used laser source are being demonstrated cutting a contour out of 2-mm CFRP with an effective average cutting speed of 0.9 m/min and thermal damage smaller than 20 µm.