Finite element modeling the influence of edge roundness on the stress and temperature fields induced by high-speed machining

High-speed machining (HSM) may produce parts at high production rates with substantially higher fatigue strengths and increased subsurface micro-hardness and plastic deformation, mostly due to the ploughing of the round cutting tool edge associated with induced stresses, and can have far more superior surface properties than surfaces generated by grinding and polishing. Cutting edge roundness may induce stress and temperature fields on the machined subsurface and influence the finished surface properties, as well as tool life. In this paper, a finite element method (FEM) modeling approach with arbitrary Lagrangian Eulerian (ALE) fully coupled thermal-stress analysis is employed. In order to realistically simulate HSM using edge design tools, an FEM model for orthogonal cutting is designed, and solution techniques such as adaptive meshing and explicit dynamics are performed. A detailed friction modeling at the tool-chip and tool-work interfaces is also carried out. Work material flow around the round edge cutting tool is successfully simulated without implementing a chip separation criterion and without the use of a remeshing scheme. The FEM modeling of the stresses and the resultant surface properties induced by round edge cutting tools is performed for the HSM of AISI 4340 steel. Once FEM simulations are complete for different edge radii and depths of cut, the tool is unloaded and the stresses are relieved. Predicted stress fields are compared with experimentally measured residual stresses obtained from the literature. The results indicate that the round edge design tools influence the stress and temperature fields greatly. An optimization scheme can be developed to identify the most desirable edge design by using the finite element analysis (FEA) scheme presented in this work.