Investigation on high-aspect-ratio silicon carbide ceramic microchannel by using waterjet-assisted laser micromachining

The challenging machinability of silicon carbide (SiC) ceramic, due to its hardness and brittleness, has traditionally constrained its machined quality and the creation of functional surfaces. Compared to direct laser machining (DLM), waterjet-assisted laser micromachining (WJALM) is an alternative technique for SiC ceramic that is capable of reducing thermal-induced damages. In this paper, high-aspect-ratio (HAR) microchannels are fabricated on silicon carbide ceramic by WJALM, and its effectiveness is verified through comparative experiments with DLM. The effects of the parametric combination of waterjet and laser parameters on machining responses of geometric structural features and sidewall surface quality are investigated by controlled variable experiments. The results revealed that HAR microchannels with almost no recast layers could be obtained when the SiC workpiece was fabricated by a nanosecond laser under the flowing water medium layer, and higher average laser power of 27 W, lower scanning speed of 600 m/s, and medium waterjet velocity of 12/16 m/s contributed to larger aspect ratio, more ablation area and superior sidewall quality of HAR microchannels.