Investigation of effect of cutting parameters and tool nose radius on cutting forces and surface roughness in finish hard turning of AISI D2 steel with CBN tool

Abstract

Because of its excellent wear and abrasion properties, AISI D2 steel is widely used as a material for bearing races, forming dies, punches, forming rolls, etc. Understanding of the mechanics of oblique turning of hardened materials is important to industries manufacturing components like bearings, dies and tools. This research describes investigation of effect of cutting parameters (cutting speed, feed), tool geometries (tool nose radius) on cutting forces (cutting force, radial force and axial force) and surface roughness of AISI D2 steel using cubic boron nitride (CBN) tool. Experiments were conducted based on full factorial design of experiment. Results shows influence of different cutting conditions on cutting forces and surface roughness. Forces in axial, radial and cutting directions vary with the different values of cutting speed, feed and nose radius at constant depth of cut during hard turning. Initially, force model is developed based on cutting parameters (i.e. cutting speed and feed) and tool nose radius and further it is extended by considering progressive flank wear. Empirical model of cutting forces shows best fits with cutting conditions (i.e. cutting speed and feed) and tool geometries (i.e. tool nose radius, inclination angle and rake angle). Experimental observation shows that feed is most significant parameter affecting cutting force, radial force and axial force followed by nose radius and cutting speed. Cutting forces are linearly proportional to feed and nose radius whereas, it is inversely proportional to cutting speed. A linear exponential model of surface roughness shows simultaneous effect of cutting speed, feed and nose radius. Feed contributes significantly to surface roughness than tool nose radius and cutting speed. Empirical models of forces and surface roughness are validated with new set of experiments and found to be with reasonable accuracy of prediction within limits of cutting parameters and tool geometry considered. newline newline