(ICALEO 2006), Paper No. 310, Laser Institute of America, Publication No 599, Vol. 99, ISBN 0-912035-85-4 (2006)
P.W. French, M. Naeem, M. Sharp, K.G. Watkins.
Abstract: Laser percussion drilling is now a well-established material processing technique in the aerospace industry. These holes are important as they allow boundary layer cooling of the component. Of the two different drilling techniques, percussion and trepanning, percussion drilling is preferred as it allows the reduction in the cycle time of the component. This is a very important factor as some components can have up to 40,000 holes. One of the major aspects that concern the aerospace industry is the quality of the holes. Hole geometry such as taper, roundness and variation between holes must be within certain tolerances if the component is going to be used in an aero engine. Other important factors with respect to hole quality are metallurgical issues concerning recast layer and micro-cracking with in the hole. Using factorial experimental design a study was undertaken to look at various pulse shapes. An investigation into how the temporal shape of a drilling pulse interacts with other drilling factors was investigated. Interactions between the different pulse shapes and other important drilling parameters were also examined and best-drilling practices are discussed.