Abstract The aim of this research work is to optimize material removal process parameters using CNC turning operation to get the desired value of the surface roughness. With an orthogonal array of L27, the Taguchi approach is used where three levels of each parameter are taken into account, which are cutting speed, feed and nose radius. The experiments were done on EN8D carbon steel and a carbide insert was used for a total run of 27 experiments. Using the surface roughness tester, the roughness values were obtained. Analysis of variance (ANOVA) was executed on Minitab software to recognize the impact of individual machining parameter on surface roughness. Regression equation is prepared from the experimental data and validated by performing random experiment.