Formulation of a 3D fully coupled thermo-mechanical finite element model for simulating orthogonal cutting of Ti-6Al-4V

The present investigation involved the formulation of a 3D fully coupled thermo-mechanical finite element model for the orthogonal cutting of Ti-6Al-4V alloy using the general purpose, commercial software ABAQUS. The workpiece material was assumed to follow the Johnson-Cook constitutive relationship while the Cockcroft-Latham damage criterion was implemented into the program via the development of a VUMAT user subroutine in order to simulate chip formation/morphology. Similarly, the cutting tool was defined as a deformable body based on the mechanical/physical properties of ISO K20 tungsten carbide. Predicted response measures such as cutting forces were compared and validated against experimental data for cutting speeds of 60, 90 and 120m/min and a fixed feed of 0.125mm/rev. Simulated cutting forces showed good agreement with corresponding experimental results (3-15% error) while predicted process temperatures agreed well with results published by other researchers. Modelled serrated chip morphology was validated by micrographs of etched chip cross sections, which suggested that the VUMAT user subroutine employed was appropriate.