Prediction of cutting force in ultra-precision machining of nonferrous metals based on strain energy

Abstract

The effects of the nonuniform cutting force and elastic recovery of processed materials in ultra-precision machining are too complex to be treated using traditional cutting theories, and it is necessary to take account of factors such as size effects, the undeformed cutting thickness, the tool blunt radius, and the tool rake angle. Therefore, this paper proposes a new theoretical calculation model for accurately predicting the cutting force in ultra-precision machining, taking account of such factors. The model is first used to analyze the material deformation of the workpiece and the cutting force distribution along the cutting edge of a diamond tool. The size of the strain zone in different cutting deformation zones is then determined by using the distribution of strain work per unit volume and considering the characteristics of the stress distribution in these different deformation zones. Finally, the cutting force during ultra-precision machining is predicted precisely by calculating the material strain energy in different zones. A finite element analysis and experimental data on ultra-precision cutting of copper and aluminum are used to verify the predictions of the theoretical model. The results show that the error in the cutting force between the calculation results and predictions of the model is less than 14%. The effects of the rake face stress distribution of the diamond tool, the close contact zone, and material elastic recovery can be fully taken into account by the theoretical model. Thus, the proposed theoretical calculation method can effectively predict the cutting force in ultra-precision machining.