Study on mechanism of spray-mist-assisted laser processing of carbon fiber reinforced plastic

Carbon fiber reinforced plastic (CFRP) have wide application prospects due to its excellent mechanical prop-erties. However, laser processing of CFRP will lead to a series of thermal damages, resulting in the mechanical properties being eroded. In this study, a method of spray mist to impact the wall to form a flowing and thin water film to assist laser low thermal damage processing for CFRP is carried out. Based on the oxidation reaction of oxygen to accelerate the etching efficiency of CFRP, a mixture of nitrogen and oxygen is used to assist the siphon nozzle to generate spray mist.The design of experiments (DOE) is used to study the influence of process pa-rameters on machining, and the process parameters were optimized. The loss characteristics of spray mist on laser energy transmission were studied by the beam analyzer and the laser power meter. The dynamic ablation process of CFRP was photographed in situ by a high-speed camera, and the mechanism of spray mist-assisted laser processing of CFRP was studied by X-ray diffraction. The results show that the offset distance de-termines the machining quality, and the machining quality is significantly affected by laser power and cutting speed. When the oxygen content is 30%, a relative balance of cold and heat can be achieved, and a higher processing quality can be obtained. Spray mist causes laser scattering; the irradiated area and the energy loss increase; the smaller the offset distance, the larger the laser energy loss and the irradiated area. Most impor-tantly, compared to the direct impact of the spray, the directional flow of the water film is beneficial to ensuring the quality and continuity of the laser processing.

Automated summary

This study proposes a method of spray mist-assisted laser processing for CFRP, which uses a flowing and thin water film generated by spray mist to reduce thermal damage. The process parameters were optimized to improve the machining quality. The results show that spray mist causes laser scattering and energy loss, while the directional flow of the water film is beneficial for the quality and continuity of laser processing.