Wear signature on hole defects as a function of cutting tool material for drilling 3D interlock composite

The aim of this paper is to study the influence of machining parameters and tool geometry on the machining quality and the mechanisms of wear that develop when drilling a new 3D woven composite material. Various frictional contacts were analyzed using the cutting tools selected (a diamond-coated carbide twist drill and a core drill with electro deposited diamond grains). The signature of wear on the wall of the holes was investigated at both macro and micro levels using the cutting force measurements and SEM observations combined with 3D roughness measurements. The damage generated on the wall of the hole was uniformly distributed and was not affected by the fiber orientation when the core drill was used. However, with the twist drill, the damage observed was strongly influenced by the fiber orientation. In addition, wear tests indicated that the signature of the wear on the wall was different from one geometry to the other. When the core drill was used, the grain removal and grain smoothing of the diamond grains was observed. Moreover, when the twist drill was used, the tool wear mechanisms were driven by abrasion phenomena on the flank face accompanied with the delamination of the diamond layer. Finally, core drills were found to offer excellent wear resistance compared to twist drills during the drilling of 3D woven composites. (C) 2015 Elsevier B.V. All rights reserved.