High ablation rate laser processing of CFRP for repair purpose

The use of Carbon Fiber Reinforced Plastics (CFRP) in industrial mass production has been rising dramatically in the last few years due to its light weight and high mechanical strength. However, like any other material, structures made of CFRP may get damaged at high service load or by unpredictable impacts. The aim of this study was to maximize the ablation rate in order to optimize the removing of the damaged material for industrial applications. A nanosecond laser with an average power of 21 W and a galvano scanner were used to treat CFRP surface. The strategy presented in this paper comprised two consecutive steps of grooving and removing. In the grooving step, the fibers cut into small fragments. In the removing step, the defocused beam scanned between two adjacent grooves with sufficient energy to sublimate the plastic matrix. By implementing the "grooving/removing" strategy, an ablation rate of 1.8 mm3/s was achieved which is about four times higher than ablation with pure sublimation.