Comparative assessment of two ceramic cutting tools on surface roughness in hard turning of AISI H11 steel: including 2D and 3D surface topography

This paper presents a comparison of surface roughness between both ceramic cutting tools namely, TiN coated mixed ceramic CC6050 and uncoated mixed ceramic CC650 when machining hardened hot work steel X38CrMoV5-1 [AISI H11] treated at 50 HRC. A mathematical model, relating surface roughness criteria and main factors such as cutting radius, cutting speed, feed rate, and depth of cut, was developed using response surface methodology (RSM) and its adequacy was checked by regression analysis. The effect of cutting parameters on surface roughness is evaluated and the optimum cutting conditions to minimize the surface roughness are determined. A multiple linear models have been established between the cutting parameters and the surface roughness using response surface methodology. The experimental results reveal that the most significant machining parameter for surface roughness is the feed followed by cutting radius. Also the determined optimal conditions really reduce the surface roughness on the machining of AISI H11 steels within the ranges of parameters studied. In addition, excellent surface roughness was obtained in hard turning using CC650 tools. The coated ceramic tools had no advantage over CC650 from the point of view of surface roughness.