Parameter study and multi-objective optimization for water jet guided laser drilling of SiC/SiC ceramic matrix composites

Silicon carbide fiber-reinforced silicon carbide ceramic matrix composites (SiC-CMCs) are promising aerospace materials, yet their inherent heterogeneity and anisotropy pose formidable challenges for high-precision, low-damage hole drilling. Water jet guided laser (WJGL) processing offers a viable solution, though it remains susceptible to edge chipping. This study develops a novel quantitative edge chipping evaluation methodology by integrating conventional one- and two-dimensional edge chipping factors (ECFs), enabling comprehensive damage characterization. Through systematic experimentation and multi-objective optimization, we analyze the coupled effects of laser power, scanning speed, and water jet pressure on edge chipping, dimensional accuracy, and processing efficiency. Scanning speed emerges as the dominant parameter, contributing 52.40 % to processing efficiency while significantly influencing chipping. Laser power and scanning speed primarily affect entrance chipping, whereas exit chipping is more sensitive to elevated scanning speed and water pressure. Optimization yields substantial improvements: entrance/exit chipping factors decrease by 33 % and 11 %, respectively; while entrance/exit dimensional accuracies improve by 34 % and 68 %, respectively, and processing efficiency increases by 58 % (achieving 3.794 s per hole). This study provides an effective technical solution for high-quality, efficient, and low-damage hole-making of SiC-CMCs.