STATISTICAL ANALYSIS OF SURFACE ROUGHNESS BY DESIGN OF EXPERIMENTS IN HARD TURNING

Abstract

In the present study, an attempt has been made to investigate the effect of cutting parameters (cutting speed, feed rate and depth of cut) on surface roughness in finish hard turning of 42CrMo4 steel using coated mixed ceramics tool AL₂O₃/Tic which is approximately composed of 70% of Al₂O₃ and 30%of Tic. The relationship between cutting parameters (cutting speed, feed rate and depth of cut) and machining output variables (surface roughness) through the response surface methodology (RSM) are analysed and modelled. The combined effects of the cutting parameters on machining output variables are investigated while employing the analysis of variance (ANOVA). The quadratic model of RSM associated with response optimization technique and composite desirability was used to find optimum values of machining parameters with respect to objectives (surface roughness). The results show that the feed rate is the dominant contributor to the roughness  parameters Ra and R_t accounting for 57.49% and 61.67%, respectively. A quadratic model best describes the variation of surface roughness with major contribution of feed rate, cutting speed and secondary contributions of interaction effect of cutting speed.

DOI: http://dx.doi.org/10.5755/j01.mech.18.5.2704