Modelling and analysis of the specific cutting energy for ultra-precision diamond cutting of Ti6Al4V alloy

Ultra-precision diamond cutting (UPDC) is a promising method for fabricating precision parts of titanium alloys. Although energy consumption models have been proposed for conventional cutting methods with macro-cutting scale, few studies focus on the modelling of specific cutting energy for UPDC of titanium alloys with micro/nano-cutting scale. This study proposes an analytical specific cutting energy (SCE) model by fully considering two-phase material microstructures, spring back, size effect, cutting edge effect, temperature evolution and tool-chip frictional states. The theoretical and experimental results show that the significant cutting edge effect and large spring back amount jointly leads to the very high SCE at small undeformed chip thickness (UDCT). The minimum SCE is achieved at the transition UDCT where the cutting mechanism transforms from ploughing to shearing. Moreover, the severe resistance of dislocation movement induced by viscous drag effect results in the slightly increased SCE with increasing cutting speed. The heat accumulated at high cutting speeds can further increase the SCE through increasing the spring back amount of finished surface. The simulated SCE values are in good agreement the experimental results within an error of 6.3 %. By considering the round tool nose and tool wear rate, an energy-oriented machining parameters optimization method is proposed and validated to minimize the SCE in UPDC of titanium alloys.