The influence of cutting edge sharpness on surface finish in facing with round nosed cutting tools

The range of and particularly the minimum surface roughnesses achievable mainly with cemented carbide but also with single crystal diamond round nosed turning and facing inserts has been experimentally studied, machining aluminium and steel on engineering and precision lathes. Characteristic variations of machined surface profile with feed rate as well as insert edge sharpness and roughness measurements are reported. For aluminium faced by carbide inserts on precision lathes, insert edge radius (re) rather than feed marks determined Rz at low feeds, with Rz ≈0.02re. For steel work material, its properties rather than the insert edge radius became the Rz determining factor.