Investigation on the effect of turning operation on surface roughness of hardened C45 carbon steel

The machining parameters of any machining operation highly affect the surface quality of a component. The objective of this investigation was to find the best possible machining parameters in order to obtain better surface quality. CNC turning was carried out with titanium nitride-coated carbide insert on hardened C45 medium carbon steel. The turning parameters, namely spindle speed, feed rate, depth of cut and nose radius were chosen to conduct the experiments based on L-9(3)(4) orthogonal array. Surface roughness of the machined specimens was measured with a surface roughness tester. A mathematical model representing average surface roughness was developed using regression analysis with the help of MINITAB software. The optimum machining conditions for minimum surface roughness were determined through Taguchi technique and genetic algorithm and verified with confirmation experiments.