Optimisation of machining and geometrical parameters in turning process using Taguchi method

Abstract

One of the most important factors that adversely affect quality of turning process is flank-wear. The flank-wear influences surface roughness and dimensional accuracy of finished product. Both flank-wear and surface roughness depend upon machining parameters and geometry of cutting tool inserts. Therefore, in order to ensure minimum flank-wear and surface roughness, it is necessary to optimise these machining and geometrical parameters in turning process. In the present work, seven parameters — cutting speed [m/minute], feed rate [mm/rev], depth of cut [mm], material type (hardness value HB), cutting-insert-shape, relief angle [°] and nose radius [mm] — were selected. Experimental layout using Taguchi’s L 18 orthogonal array was employed. Flank-wear and surface roughness were minimised using Taguchi’s signal-to-noise ratio concept with lower-the-better quality characteristic. Experimental results demonstrate the effectiveness of the Taguchi’s optimisation approach. Optimal setting of machining and geometrical parameters yielded significant reduction in flank-wear and surface roughness value of 53.86% and 15.95%, respectively. A validation experiment was also carried out for confirmation. The optimum flank-wear and surface roughness were 0.057 mm and 1.0248 /μη, respectively. The significance test using analysis of variance showed that the cutting-insert-shape, feed rate, cutting speed and material hardness were the most critical parameters with percentage of contribution 36.94%, 30.82%, 10.47% and 8.87%, respectively.