Modeling of variable friction and heat partition ratio at the chip-tool interface during orthogonal cutting of Ti-6Al-4V

The extreme contact conditions and temperature at the tool-chip interface in machining make it difficult to access the region and evaluate their tribological properties. To overcome this issue, in the author's earlier work, a new 'pin-on-workpiece' tribometer was developed that replicates machining tribological conditions and evaluates the velocity-dependent adhesive coefficient of friction (CoF) and heat partition ratio (HPR). In this work, a 2-D finite element model for orthogonal cutting is developed using ABAQUS Tm that takes into account the effect of variable CoF and HPR and assesses their effect on cutting forces and temperature. It is observed that as feed rate increases, the location of maximum temperature along chip-tool interface shifts from 1 mm away from the tool-tip, to closer to the tool-tip. Using the variable CoF, the maximum tool temperature reduces to 490 degrees C from 750 degrees C using the constant friction condition. Also, using the variable CoF, the error in cutting force model is reduced to 13 % from 22 % for the constant friction model.