Tool wear in drilling of composite/titanium stacks using carbide and polycrystalline diamond tools

► When drilling CFRP-Ti stacks using the WC drills, Ti adhesion was a predominant tool wear factor, covering the entire cutting edges. ► PCD drills on the other hand, showed less titanium adhesion, but had a significant amount of cutting edge chipping. ► Abrasion, by the carbon fiber and hard inclusions in Ti, and adhesion of titanium were found to be the dominant tool wear mechanisms. ► Higher torque and thrust values were observed at the higher spindle speeds which caused a significant increase in tool wear due to the higher temperature generated, especially when drilling the Ti plates.