Ti6Al4V metal cutting chip formation experiments and modelling over a wide range of cutting speeds

Measured forces, chip geometry and tool temperatures from machining a mill annealed Ti6Al4V at cutting speeds mainly from 1 to 100 m/min, but in some cases down to 0.1 m/min, are reported, as well as mechanical testing of the material. Finite element simulations with inputs the measured flow stress, and subsequently a small high temperature strain hardening recovery correction, and a failure model calibrated from the cutting tests at speeds from 1 to 10 m/min, give satisfactory agreement with the higher speed tests once surface strain hardening and damage from the previous pass of the tool are taken into account. This paper's originality is firstly to show that more complicated flow stress models involving large strain softening are not needed provided shear failure is included; and secondly its failure model: this proposes a non-zero failed shear stress depending on local pressure and temperature. The simulations provide relations between tool mechanical and thermal loading and cutting conditions to aid process improvement.