An analytical model for micro-cutting considering the cutting tool edge radius effect and material separation

Severe plastic deformation occurs in micro metal cutting process; meanwhile, new surfaces are generated due to the material separation caused by ductile fracture. The energy required for the formation of the new surfaces is of kJ/m2, which should not be neglected in the analysis of micro-cutting. In this work, an analytical model is developed focusing on the analyses of the micro metal cutting process with no stable built-up edge, in which the effects of both edge radius and material separation are taken into account. The cutting tool edge geometry is simplified with the effective rake angle. On the basis of slip-line field theory, the equation of the cutting power is derived. Applying the minimum energy principle, two nonlinear equations are obtained, through which the shear angle and the minimum chip thickness can be estimated simultaneously. The model is examined through the experiments; the investigations show that the calculation results of cutting force and shear angle agreed with the experimental measurements very well. The effects of fracture toughness, shear yield stress, and friction angle to the micro-cutting process are investigated. The numerical results show that the friction angle affects the cutting force and the shear angle greatly.