Study of Droplet Spray Behavior of an Atomization-Based Cutting Fluid Spray System for Machining Titanium Alloys

Abstract

The atomization-based cutting fluid (ACF) spray system has been found to be effective for improving the tool life and overall productivity during the machining of titanium alloys like Ti–6Al–4 V. The aim of this research is to study droplet spray characteristics of an ACF spray system including droplet entrainment zone (e.g., angle and distance) and droplet-gas co-flow development regions with respect to three ACF spray parameters, viz., droplet and gas velocities, and spray distance. ACF spray experiments are performed by varying droplet and gas velocities. Machining experiments are performed in order to understand the effect of the droplet spray behavior on the machining performance, viz., tool life/wear, and surface roughness during turning of a titanium alloy, Ti–6Al–4 V. The flow development behavior with respect to the spray distance is studied by modeling the droplets entrainment mechanism. The model is validated by the ACF spray experiments. Experiments and the modeling of flow development behavior reveal that a higher droplet velocity and a smaller gas velocity result in smaller droplet entrainment angle leading to a gradual and early development of the co-flow, and a better distribution of the droplets across the jet flare. Machining experiments also show that a higher droplet velocity, a lower gas velocity and a longer spray distance significantly improve tool life and surface finish.