This paper presents a study of the development of a surface roughness model for turning of mild steel with coated carbide tools.
The model is developed in terms of cutting speed, feed rate and depth of cut, using response surface methodology. Machining tests
were carried out with TiN-coated carbide cutting tools under various cutting conditions. First-order and second-order model predicting
equations for surface roughness have been established by using the experimental data. The established equation shows that
the feed rate was main influencing factor on the surface roughness. It increased with increasing the feed rate but decreased with
increasing the cutting speed and the depth of cut, respectively. In addition, analysis of variance for the second-order model shows
that the interaction terms and the square terms are statistically insignificant. The predicted surface roughness of the samples has
been found to lie close to that of the experimentally observed ones with 95% confident intervals. Moreover, it is seen that the
first-order effect of feed rate and cutting speed is significant while depth of cut is insignificant.