Laser processing of small holes with large aspect ratio in SiC_f/SiC composites

The processing of small holes with large aspect ratio in SiC_f/SiC ceramic matrix composites (SiC_f/SiC composites) are characterized by anisotropy, high hardness, and low electrical conductivity, which makes it difficult. Femtosecond laser processing and water-guided laser processing belong to the advanced laser processing methods, which have the advantages of controllable processing quality, automated processing, and low processing cost, and are the preferred technological solutions to solve the large aspect ratio of small holes in SiC_f/SiC composites. Small holes with an aspect ratio of 10 are processed in SiC_f/SiC composites by using femtosecond laser rotary drilling (FLRD) and water jet guided laser drilling (WJGLD). The morphology and physical phases of the entrance, exit, and wall of the small holes were analyzed, and the hole diameter, hole wall roughness, and processing efficiency of the small holes were compared. The results show that the exit quality of the holes processed by laser is better than the entrance quality, and the small holes processed by femtosecond laser have the advantages of sharp orifice, good roundness, and small taper, while the water guide laser processing has the advantages of clean orifices and hole walls, and high processing efficiency. To address the demand for small holes with large aspect ratios in heat-resistant components of SiC_f/SiC composites, suitable drilling technology should be selected by considering factors such as processing quality, processing efficiency, and processing conditions.