Thrust force and delamination of core-saw drill during drilling of carbon fiber reinforced plastics (CFRP)

Due to the inherent anisotropy and inhomogeneous nature of polymer-based composite materials, their cutting mechanism differs in many respects from conventional metallic materials. Amongst all machining operations, drilling using a twist drill is the most commonly applied method for generating holes for riveting and fastening structural assemblies. Most of the previous research correlates the drill geometry and feed rate to thrust force and delamination on the performance of a twist drill. The Taguchi method has been used to solve many engineering problems. In this investigation, drilling-induced thrust force and delamination by core-saw drill during drilling CFRP laminates were selected as quality character factors to optimize the drilling parameters to obtain the smaller-the-better characteristics. For thrust force and delamination quality character factors, the optimum conditions in drilling were also A(1)B(1)C(3), (i.e., diameter ratio=0.55, feed rate=8 mm/min and spindle speed=1,200 rpm).