Experimental analysis and optimisation of tool wear in dry machining of aluminium alloys

In machining, coolants and lubricants improve machinability, increase productivity by reducing the tool wear and extend the tool life. However, the use of cutting fluids in metal working operations may seriously degrade the quality of the environment. Consequently, many governments recommend the manufacturers to reduce the volume and the toxicity of their cutting fluids. Up to now, dry machining has remained a real challenge for the industrial world, particularly in aerospace engineering. The experimental approach taken in this study resulted in the development of both optimised tool geometry and optimised cutting conditions for drilling aluminium alloys without the need for lubrication. The experimental investigations were carried out with WC–Co cemented carbide drills. The use of diamond as coating material allowed to extend the tool life. The combination of the optimised tool geometry and the cutting conditions entails a high surface quality, a good dimensional accuracy of the machined material and ensures a long lifetime to the drill. Besides, a numerical calculation with Third Wave AdvantEdge™ finite element software was used to predict the tool–chip interface temperature, which is the major parameter inducing tool wear in dry drilling.