Machining millimeter-scale deep holes in SiCf/SiC material using femtosecond laser filamentation effect

A 3.5 mm thick SiCf/SiC material was drilled in air environment using a femtosecond laser filament effect. The surface morphology of deep micropores was observed by scanning electron microscopy and the depth and profile of the pores were observed using μm-CT. The variation of entrance diameter, exit diameter and depth variation with laser focus position and processing time was further analyzed. The results showed that as the processing time of femtosecond laser increases, the ablation threshold of the material reached saturation. The exit and entrance diameter also stopped increasing and the aperture tend to saturate. The focus entered the interior of the material, allowing the location of the peak power near the surface of the material. So the entrance aperture was of good quality and the exit aperture was round.