Study on the mechanism of ultrasonic-assisted laser processing carbon fiber reinforced plastics in ethanol solution

The water-assisted laser processing of carbon fiber-reinforced plastics (CFRPs) can reduce thermal damage. However, the machining quality and efficiency will be reduced by laser-induced cavitation bubbles when laser processing in the water. A method of in situ ultrasonic vibration-assisted laser processing of CFRPs in the ethanol solution was proposed to reduce the adverse effect of cavitation bubbles on machining. The influence of process parameters on machining was studied by the design of experiments. The dynamic ablation behavior of the laser-ablated area was captured in situ by a high-speed camera. The machining mechanism was analyzed. The results show that the volume of the cavitation bubble is reduced in the ethanol solution, and the laser scattering is reduced. The machining quality is improved. When the volume fraction of ethanol exceeds 40%, the laser extinction rate is increased by the accumulation of cavitation bubbles. The heat-affected zone (HAZ) and the etching depth were reduced by 57% and 25%, respectively. The ultrasonic vibration can explode the cavitation bubble, and the interference of the cavitation bubble to the laser is reduced. The effect of mechanical erosion is enhanced. The etching depth was increased by 119%. The cooling effect of the ablated area is enhanced by ultrasonic vibration. The HAZ is reduced by 57%. According to the findings of this study, the material deposition can be effectively reduced when the method of the paper is used, a clean groove is generated, the fiber pull-out is improved, and better machining quality can be obtained.