Preliminary studies into the machining of certain aerospace materials using excimer laser radiation have been performed. Burn-through experiments were conducted using KrF (248nm) laser radiation in the fluence and PRF ranges 0-6J/cm2 and 1-50Hz respectively. In particular, woven Kevlar (in various forms) and carbon fibre composite structures have been machined with excellent edge quality and no visible degradation of the surrounding bulk material (SEM photographs are presented). Fluence thresholds for material removal exist and occur in the range 0.1-0.5J/cm2 for the above materials. Maximum observed removal rates have been measured as ~1-1.2μm/pulse and ~0.4μm/pulse for Kevlar and carbon fibre composites respectively at a fluence of ~6J/cm2. Complemetary studies for Kevlar are also reported using XeCl (308nm) laser radiation in the fluence and PRF range 0- 1.5J/cm2 and 50-500Hz. Machining rates are comparable to those at 248nm. Material removal rates per pulse at both wavelengths appear independent of PRF values. Both pre-cured and cured composites exhibit good matrix stability at the machined walls and there is no visual evidence of curing occurring during excimer laser irradiation. Sooty (probably carbon rich) debris was observed around the irradiated zone, the extent of which increased with increasing fluence. From extrapolation of etch rate data, industrial cutting rates are anticipated.

Date Published: 26 October 1989
PDF: 9 pages
Proc. SPIE 1132, High Power Lasers and Laser Machining Technology, (26 October 1989); doi: 10.1117/12.961570

Published in SPIE Proceedings Vol. 1132:
High Power Lasers and Laser Machining Technology
Michel Gaillard; A. Quenzer, Editor(s)