Abstract | The main objective of this work is to understand the effect of the MQL parameters; namely, oil flow rate, air flow rate and nozzle distance from the cutting zone, on the flow characteristics in order to optimise the cooling and lubrication capacities of the jet for machining applications. Flow visualisation experiments were performed for different air and oil flow rates and distances from the nozzle using phase Doppler anemometry (PDA). The visualisation results, such as, the droplet size and velocity vector were used to identify the optimum MQL conditions to achieve the desired flow characteristics for machining applications. It was found that a spray with high air flow rate and high oil flow rate would give an axial, symmetrical, coherent, and undisturbed spray, which is characterised by small droplet size and high velocity. This spray is optimum for machining due to its ability for better penetration and cooling effect in the cutting zone. Milling tests were performed on Ti-6Al-4V alloy to validate the effect of MQL parameters on the machining performance, in terms of cutting forces, surface roughness and tool temperature. |
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