RMS-based optimisation of surface roughness when turning AISI 420 stainless steel

The aim of this investigation is to determine the correlation between the cutting conditions such as cutting speed, feed rate, and depth of cut; and surface roughness parameters (Ra, Rq, Rt, Rp, and R3z). The case of turning operation of martensitic stainless steel AISI 420 using CVD coated carbide tool is studied. Full factorial design (43) was adopted. Statistical analysis ANOVA and response surface methodology (RSM) was used to develop quadratic regression models and to determine optimum cutting conditions. It was found that the feed rate (f) is the highest factor influenced the surface roughness parameters when compared with speed and depth of cut. Moreover, a good agreement was observed between the predicted and the experimental surface roughness criteria. The use of lower cutting speed, lower feed rate, and lower depth of cut ensures minimum surface roughness variations.