Research on laser-assisted orthogonal micromachining technology of C_f/SiC composite

Carbon fiber-toughened silicon carbide composite matrix composite (C_f/SiC composite) occupies an important position in the field of aerospace due to its excellent mechanical properties. Because C_f/SiC composite have good high temperature resistance and hardness, machining traditional C_f/SiC composite is a difficult and time-consuming process. In this paper, two-dimensional braided C_f/SiC composite is used as the object, and a new laser-assisted machining orthogonal experiment system for processing C_f/SiC composite is developed by combining laser and conventional machining. The influence of laser-assisted orthogonal micromachining (LAOM) and conventional orthogonal micromachining (COM) input variables on the machining performance of C_f/SiC composite is mainly studied. By comparing the processing characteristics of the workpiece surface roughness, surface micro-topography, etc., the process benefits of laser processing variable changes are analyzed. The orthogonal experiment method is used to analyze the influence of factors such as machining speed, machining depth, and laser power on surface quality. The experiment results showed that the surface quality obtained by LAOM was better than that of COM. The machining depth had the most significant effect on the surface roughness, followed by the laser power, and the machining speed exerted the lowest effect on the surface roughness. Considering the surface quality requirements, the smallest surface roughness of the workpiece was obtained and the surface roughness Sa value was 3.841 μm with the optimal combination: a machining depth of 20 μm, a laser power of 20 w, and a machining speed of 300 mm/s. Microscopic analysis revealed that there were no pits, fiber tearing, pulling out, and other defects on the surface of the LAOM workpiece, and the surface was relatively flat and smooth.