An experimental study on drilling of unidirectional GLARE fibre metal laminates

Drilling operations in glass laminate aluminium reinforced epoxy (GLARE) hybrid laminates require different optimisation of machining parameters from those used in the drilling of its constituents, aluminium alloy and glass fibre reinforced polymers (GFRP). Accurate selection of drilling parameters is essential in order to achieve high quality holes and to minimise any defects that may compromise the long-term structural integrity of the machined component. This work conducted drilling experiments on unidirectional (UD) grade 2B and 3 GLARE composites using ϕ6 mm solid carbide TiAlN coated twist drills. The drilling parameters were analysed to study their impact on the thrust force, torque and surface roughness, whereas hole quality and tool condition were inspected using optical microscopy techniques. The results indicated that the ply orientation had no effect on the cutting forces, and surface roughness was found to be higher for grade 3 than for grade 2B for similar cutting parameters. Both feed rate and spindle speed showed to have a significant impact on the cutting forces and the hole quality.