Enhanced dry machinability of TC4 titanium alloy by longitudinal-bending hybrid ultrasonic vibration-assisted milling

While cutting fluids are widely used in industrial mechanical machining of difficult-to-cut materials, achieving environmentally-friendly dry milling without the usage of cutting fluids by utilizing advanced manufacturing techniques makes significant sense for facilitating cleaner production. In the present work, we demonstrate the feasibility of enhancing dry machinability of TC4 titanium alloy by applying the newly proposed longitudinal-bending hybrid ultrasonic vibration-assisted milling (LBVAM), which is effective in modulating the intermittent cutting behavior between tool and workpiece material. Specifically, the kinematics and the material removal mechanisms of the LBVAM are investigated by analytical investigation, 3D finite element simulations and corresponding experiments. Simulation and experimental results demonstrate that the utilization of LBVAM enables lowering the surface roughness by 46.7% and reducing the cutting force by 43.2% from conventional milling. And the mostly prominent feature is that the surface roughness can be down to 100 nm by using the proposed LBVAM with rationally selected parameters, which is highly promising for realizing cleaner dry manufacturing of TC4 without using cutting fluids. Current work provides a feasible environmentally-friendly machining method for enhancing the dry machinability of difficult-to-cut materials.