Study on Tool Wear and Chip Formation During Drilling Carbon Fiber Reinforced Polymer (CFRP)/Titanium Alloy (Ti6Al4 V) Stacks

Composites are used in conjunction with another material to form a multi-material stack-up, which results in greater strength to weight ratios. In a wide range of aerospace applications dissimilar material stack-ups of composites and aluminium and/or titanium are used. Drilling is probably the most common machining operation applied to composites since components made out of composite materials are usually near net shaped and require only holes for assembly integration. In this investigation, experiments were conducted by varying the drilling parameters and determining the optimum cutting conditions for drilling of CFRP/Ti stacks using Genetic Algorithm (GA) optimization technique. Tool wear study was performed by drilling 100 holes each with 118° and 130° point angle drills. Less progressive tool wear and better chip evacuation was achievable in 130° point angle drills when compared with 118°point angle drills.