An investigation into the behavior of the cutting forces in precision turning

A mechanistic model of precision turning, in which the depth of the cut is made considerably smaller than the tool nose radius, based on Merchant’s analysis in 3D cutting, has been developed. Reasons were deduced to the increase of the radial force component to be greater than the tangential component. The friction coefficient at the tool chip interface during precision turning has been calculated. The developed model was verified experimentally using both annealed and hardened HSS. Moreover, due to the obsoleteness of empirical formulae established by previous investigators in the case of precision turning, new empirical formulae based on the mechanistic model are presented. In this machining operation, the behavior of the cutting forces in relation to the cutting variables, revealed their high sensitivity to tool nose radius and flank wear land width.