Numerical study of the chatter phenomenon in orthogonal turning

Abstract

Chatter is a destructive phenomenon for the surface quality of the workpiece, it occurs during machining when the system (tool-workpiece-machine) vibrates in self-excited mode. It is present by side effects such as bad surface quality, excessive noise, disproportionate tool wear. This work presents a numerical approach to establish cutting stability lobes in orthogonal metal turning. The Abaqus software is used to perform the simulations, the Johnson-Cook laws are considered for the workpiece material strength and fracture, and the Coulomb law is retained for the friction between the workpiece and the tool. An explicit scheme and the Lagrangian formulation are used for the numerical simulations. The tool is considered having longitudinal flexibility, and the thermal conductivity of the workpiece and the tool is introduced. The surface smoothness in then examined, using the arithmetic average roughness. The results are compared firstly to experimental results from literature to validate the approach. Secondly, the results are compared to numerical results from literature obtained by the MSC MARC software basing on an implicit scheme and a stick-slip arctangent friction between the workpiece and the tool.