Optimisation of cutting parameters in face milling of cryogenic treated 6061 aluminium alloy and effects on surface roughness, wear, and cutting temperatures

Abstract In addition to its usage in the defence industry, 6061 aluminium is prevalent in heavy industries like the aviation, shipbuilding and space industries. In this study, cryogenic processing was applied on the 6061-T651 aluminium alloy and the cutting inserts used, face milling procedures were carried out, and the effects of cutting parameters were examined. For the face milling procedure, cutting inserts with three different coatings (coated with TiN-TiCN-Al 2 O 3 by CVD technique, coated with TiAlN-Nano by PVD technique, and coated with AlTiN by PVD technique), three different cutting speeds (250, 350 and 450 m min −1 ) and three different feed rates (0.15, 0.30 and 0.45 mm tooth −1 ) were used. The Taguchi method was used for experimental design and optimisation, and by selecting the Taguchi L9 (3 3 ) orthogonal array, nine experiments were carried out. Surface roughness and flank wear were measured after each experiment while cutting zone temperatures were measured during the experiments. The values obtained from the experiments were optimised and assessed with analysis of variance (ANOVA), three-dimensional plots, and the regression method. After the experiments, the lowest surface roughness, flank wear, and cutting temperatures were successfully optimised with the Taguchi method. The R2 values of the mathematical models for these three parameters were obtained as 100%.