Analysis and optimization of the heat affected zone of CFRP by femtosecond laser processing

In this paper, the processing threshold fluence of the carbon fiber reinforced polymers (CFRP) by a femtosecond laser ablating at different scanning speeds is studied, and the effects of processing parameters on the width of the heat-affected zone (HAZ) are discussed. The experimental results show that the ablation threshold of the carbon fiber in CFRP is about two times that of resin at the same scanning speed. At a given scanning speed, the minimum value of HAZ can be obtained when the laser fluence used is 50 ∼ 60 times as great as the ablation threshold fluence of the carbon fiber. In addition, the width of the HAZ can be further reduced when the scanning direction is consistent the polarization angle of the linearly polarized laser. The minimum value of the HAZ obtained in the experiment is about 2 μm, which is much smaller than the value in the previous literature.