Influence of Drill Geometry Design on Drilling-Induced Damage Reduction in Fibre-Reinforced Polymeric Composites

Drilling is an extensively used manufacturing process for boring different and widely used fibre-reinforced polymeric (FRP) composite materials, among various machining operations. This process is inevitable for assembling/coupling of parts of systems. Despite of the good inherent properties of the FRP composite materials, they are not easy to drill, due to the dissimilar properties of their constituents (mainly fibre/reinforcement and matrix). More than a few drilling-induced damage (DID) on FRP composites include delamination, surface roughness, fibre-pull out/uncut, among others. They severely affect the quality, structural integrity and applications of the drilled composite components. The most rampant among these damage is delamination; either peel-up or push-out type. Importantly, these damage are frequent and attributed mainly to the geometry design of the drill bits used. It is highly germane to consider and further study the influence of the drill geometry design (DGD) on reduction of DID on FRP composite components and improve the quality of the drilled holes. Therefore, this present chapter focuses on a current status/trend in the drilling of FRP composites and comprehensively reports optimum drill geometry designs (DGDs) for different FRP composites. It was evident that a combination of an efficient drill geometry (chisel and cutting edges, helix and point angles, diameter, length, material, among others) design and suitable selected drilling process parameters (cutting speed, feed rate, depth-of-cut, material removal rate, among others) produced minimum DID on FRP composite components. This knowledge is required to guide drill designers, manufacturers, machinists and researchers in their search for high performance drilling phenomenon.