Zone-Ching Lin، نويسنده , , Yeou-Yih Lin، نويسنده ,
In this paper, the finite deformation theory and an updated Lagrangian formulation (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 and tool face. In addition, a 3D finite difference equation for heat transfer was derived. Based on this approach, a coupled thermo-elastic–plastic large deformation finite element model for oblique cutting was established, for 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 the geometrical phenomenon at the instant of chip separation from the tool face, and on both stress and temperature distributions on the chip surface, were analyzed. Finally, the effect of different cutting speeds on the residual stress, displacement and temperature distributions on the machined surface after cutting were investigated to understand the relation between the cutting speeds and the integrity of the machined surface.
During the chip deformation process, the simulated chip flow angles under the different low cutting speed conditions approximately matched with the designated tool inclination angle, which complied with the geometrical requirements of Stabler’s criterion. Further, the simulated specific cutting energy under a given low cutting speed condition was compared with the experimental data, the result of which was within an acceptable range, and the trend of specific cutting energies under the different low cutting speed conditions 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 geometrical and mechanics requirements, which verifies that the proposed model is acceptable.
Cutting speeds , Oblique cutting , Finite difference , Finite element , 3D Tool face equation