Hole Surface Topography and Tool Wear in CFRP Drilling

This paper deals with the hole surface quality when CFRP drilling. Mechanical instrumented operations have enabled to follow precisely the damage on the tool margins and the main cutting edges. The amount of uncut fibers according to the drill wear was evaluated with a roundness/cylindricity device versus the fiber's orientation and the tool damage. Thus, according to the hole's diameter tolerance, a wear criterion was defined to limit the number of holes achievable. This method has been carried out on unidirectional (UD) CFRP and then transposed on multidirectional (MD) CFRP. A model developed under Matlab was applied to predict the global topography of the hole surface.