Optimization and performance study of large aspect ratio SiC microgrooves by waterjet assisted laser machining.

Silicon carbide (SiC) ceramics hold significant application value in high-end fields such as semiconductors and aerospace due to their exceptional mechanical properties and thermal stability. Large-aspect-ratio (LAR) microgrooves in ceramics are crucial for enabling advanced functionalities in various applications, including microfluidic devices, microelectromechanical systems (MEMS), and thermal management systems, where precise control over fluid flow, structural integrity, and heat dissipation is required. However, their extreme hardness poses challenges for traditional mechanical machining, including low efficiency and severe tool wear, while laser machining is prone to defects such as heat-affected zones and recast layers. This study innovatively employs waterjet-assisted laser micromachining (WJALM), compared to conventional underwater laser micromachining (UWLM), WJALM reduces the recast layer and microcracks through the synergistic cooling and impact effects of the waterjet, while maintaining smaller surface roughness (reduce by 42%). Furthermore, this research systematically optimized the machining parameters for LAR microgrooves through orthogonal experiments and grey-relational analysis (GRA). Results identified an optimal parameter combination is a scanning speed of 800 mm/s, pulse energy of 27 W, and waterjet velocity of 16 m/s, high-quality microgrooves with an aspect-ratio (AR) of 3.66 and an ablation-area-ratio (AAR) of 0.78 can be achieved. This study provides a novel technical solution for the precision machining of hard and brittle materials, offering substantial engineering application value.