Ceramic Matrix Composites (CMCs) are widely used in the field of space/aerospace, automobile, and nuclear power plants thanks to its features of lightweight, high mechanical strength, and excellent heat resistance. Since CMCs are hard-to-process material, grinding by diamond blade or water jet-guided laser are generally applied for processing. Water molecules, however, are absorbed in the pores of CMC, and it induces hydrovolcanic explosion at high temperature operation. In this paper, we report on direct and dry cutting of CMC using Deep Ultra-Violet (DUV) laser.

ArF excimer laser is a typical high energy DUV light source. We are developing a short pulse hybrid ArF excimer laser consisting of a short pulse solid-state laser-based oscillator and an ArF excimer amplifier. The hybrid laser generates DUV light with the pulse width of below 0.5 ns and the pulse energy of above 2 mJ at the wavelength of 193nm corresponding to the photon energy of 6.4eV. Owing to the high photon energy and high pulse peak power exceeding 4 MW, the hybrid ArF laser can cut the bonding of wide band gap materials directly with less heat affected zone.

We demonstrated a laser cutting of silicon carbide ceramic matrix composite (SiC-CMC). 3x3mm squared parts were cut out from a 1mm-thick SiC-CMC plate without any cooling fluids. The processing speed and required cutting margin were 1.8 mm/min and less than 0.5mm, respectively. No significant form changes were found on cutting surface comparing with the grinding surface by diamond blade. Details of DUV laser processing and cutting quality will be presented.