The ablation threshold and incubation effect in picosecond laser surface treatment of CFRP

The ablation threshold of carbon fiber is a critical parameter to consider in the laser surface treatment of carbon fiber reinforced polymers (CFRP), as it is necessary to design process parameters based on the threshold fluence to ensure process quality and efficiency. The incubation effect is a key factor influencing the ablation threshold, and a more rational incubation model contributes to a more accurate prediction of the ablation threshold. The conventional incubation model describes the regular decrease of the ablation threshold with an increasing pulse number. However, experimental findings show that the time interval of pulses is also a significant factor affecting the ablation and incubation process. In this study, the conventional incubation model was improved by comprehensively considering the time interval and space interval of pulses, which shows better prediction ability of ablation threshold under different parameter sets. The temperature history of CFRP under picosecond laser irradiation was calculated to support the rationality of the optimized incubation model. In addition, the laser-induced periodic surface structures (LIPSS) and the ablation of carbon fibers and resin were investigated based on the ablation threshold.