Nanometer-Scale Ductile Cutting of Tungsten Carbide

Abstract

In this study, cutting experiments have been carried out with nanometer-scale chip thickness to evaluate the cutting performance of tungsten carbide material under ductile mode using a Makino V55 machine tool with CBN cutters. The cutting forces were measured using a three-component dynamometer. The machined workpiece surface topography, chip formation, and tool wear were examined using SEM. The tool flank wear, VB max , was measured using OMIS. The surface roughness was measured using a SURFTEST 301. Experimental results indicate that the radial force, F x , is much larger than the tangential force, F z , and the axial force, F y . Under different cutting conditions, three types of surfaces of the machined workpiece are achieved: ductile cutting surface, semi-fractured surface, and fractured surface. The surface roughness increased monotonically when the depth of cut and feed rate were increased. The cutting speed has no significant effect on the surface roughness. The tool wear occurs mainly on the flank face in ductile cutting of tungsten carbide, and the tool wear mechanisms are dominated by abrasion, adhesion, and diffusion. The SEM observations on the machined workpiece surfaces and chip formation indicate that the ductile mode cutting is mainly determined by the undeformed chip thickness when the tool cutting edge radius is fixed. Ductile cutting can be achieved when the undeformed chip thickness is less than a critical value.