A study of oblique cutting for different low cutting speeds

In this paper, the finite deformation theory and an updated Lagrangian form ulation (ULF) were used to describe the oblique cutting process. Either the tool geometrical location condition or the strain energy density constant was combined with the twin node processing method to be adopted as the chip separation criterion. An equation for 3D tool face geometrical limitation was established to inspect and correct the relation between the chip node a nd tool face. In addition, a 3D finite difference equation for heat transfe r was derived. Based on this approach, a coupled thermo-elastic-plastic lar ge deformation finite element model for oblique cutting was established, fo r which mild steel was used as the workpiece material and P20 as the tool. Under the different cutting speed conditions, the chip deformation process and the effect of different cutting speeds on the chip flow angle, cutting force and specific cutting energy were first explored. Then, the effect of different cutting speeds on the separation location of the chip node and th e geometrical phenomenon at the instant of chip separation from the tool fa ce, and on both stress and temperature distributions on the chip surface, w ere analyzed. Finally, the effect of different cutting speeds on the residu al stress, displacement and temperature distributions on the machined surfa ce after cutting were investigated to understand the relation between the c utting speeds and the integrity of the machined surface. During the chip deformation process, the simulated chip flow angles under t he different low cutting speed conditions approximately matched with the de signated tool inclination angle, which complied with the geometrical requir ements of Stabler's criterion. Further, the simulated specific cutting ener gy under a given low cutting speed condition was compared with the experime ntal data, the result of which was within an acceptable range, and the tren d of specific cutting energies under the different low cutting speed condit ions were the same as the experimental trends. It is obvious from the above findings that the model presented in this paper is consistent with the geo metrical and mechanics requirements, which verifies that the proposed model is acceptable. (C) 2001 Published by Elsevier Science B.V.