Studies on effect of drilling parameters on CFRP laminates using HSS, HSCO and solid carbide drills

Carbon-Fiber-Reinforced-Plastics (CFRP) are often used for hole repairs in single-thickness sheets. But in the caseof hole drilling for varying thickness, for 5-6 mm region, parameter optimization is quintessential. CFRP multilayered metallicstacks often find their uses in load-bearing applications wherein fiber pull-outs and delamination are commonly seen during drilling which can be minimized with judicious choice of the operating parameters with work-piece performance. The presentwork encompassed the machining process of composite laminates with minimal damage and ascertain the suitable tools with regard to the geometry and also to correlate delamination to different machining aspects such as those of cutting parameters, thrust force, and drilling torques. Fiber-reinforced thermoplastic was considered for the analysis. The intention was to characterize the cutting conditions in CFRPs by developing a suitable profile to drill the holes in existing machines. A detailedassessment of cutting parameters v/s thrust force was obtained. Processes such as drilling torque, delamination as well as the optimization of damage zone during such processes were achieved in this work. Different input cutting parameters were implemented on composite laminates of different thicknesses in the drilling of CFRP laminates using 3 different drills, i.e., HSS Cobalt M42.