The use of carbon fibre reinforced plastic (CFRP) and metal matrix composites (MMC) is steadily increasing as an alternative to traditional metallic materials in various industrial sectors. The overall aim of the project is to assess the machinability when drilling epoxy based CFRP and Al/SiCp MMC composites and understand its effects on feature quality and workpiece integrity. Specific objectives of the project relate to establishing preferred/optimum operating parameters (cutting speed, feed rate and drill strategies) and investigating the influence of cutting environment (dry, chilled air, high pressure internal/external supplied coolant and low pressure flood) for drilling specific composite material systems. Key response measures include tool wear/life, thrust force/torque, hole size and geometrical accuracy, hole edge quality (delamination, uncut fibres and burrs) as well as workpiece surface integrity (surface roughness, microhardness, fibre/particle pullout, subsurface damage, etc.). The latest cutting tool materials and advanced diamond coatings, drill geometry and design format (e.g. domed PCD) were assessed in an attempt to improve productivity levels, tool life and hole quality. Tool wear mechanisms and its effect on hole surface quality were also investigated.