Titanium alloys have been attracting from the more industries, especially, industry aerospace due to their very important high strength to weight ratio. Furthermore, they were classified as difficult to machine materials due to low tool life in machining processes. In this study, a FE model has been developed to simulate the turning stage of Ti-6Al-4V alloy. A 3D model with thermo-mechanical coupling has been proposed to study the influence of cutting parameters and also lubrication on the performance of cutting tools. The constants of the Johnson-Cook constitutive model of Ti-6Al-4V alloy were identified using inverse analysis based on the process parameters of the orthogonal cutting. The predictive FE model has been validated based on an orthogonal cutting test. The investigations indicated that this approach estimates the resultant cutting forces with low prediction errors. Indeed, the predicted forces showed good agreement with the experimental data, with minimum and maximum error magnitudes of 2.8 and 8.7% for cutting force, and 1.3 and 6.8% for feed force, respectively.