This paper presents an analytical method for predicting the mechanical state of a machined surface with a finite-element model of orthogonal precision cutting. A geometrical separation criterion for the workpiece at the front edge of the tool is also proposed instead of other criteria, and the application of the method is discussed. The flow stress of oxygen-free high-conductivity copper (OFHC copper) was taken as a function of strain, strain rate and temperature in order to reflect realistic behavior in metal cutting. In this paper, a diamond tool was used to conduct the ultra-precision cutting of the OFHC copper. Through the simulation, the residual stress and strain distributions within the machined sub-layer were calculated analytically, the calculated cutting force being found to agree with the experimental results. The simulation results indicate that as far as the impact of temperature, strain and strain rate on OFHC copper is concerned, that of temperature is the most dramatic. The effect of temperature leads to a smaller residual stress in a machined workpiece and limited deformation of the workpiece surface. If the effect of temperature is not considered, the greater is the cutting velocity, the greater is the residual stress of the workpiece and the greater is the deformation of the workpiece surface. (C) 1997 Elsevier Science S.A.
