Hybrid Cooling and Lubricating Technology for CNC Milling of Inconel 718 Nickel Alloy

Inconel 718 is widely used in aerospace, marine, oil and gas and gas turbine industries due to its unique material properties. These material properties such high strength, high hardness and high hot hardness have also made Inconel 718 a difficult to machine material. Machining Inconel 718 is associated with poor tool life and surface integrity resulting in high manufacturing costs and low productivity. Minimum quantity lubricant (MQL) and cryogenic machining are alternative cooling/lubricating techniques for improving machinability of difficult to machine materials. However, their application is limited in machining Inconel and most studies are concentrated on turning. In this paper, MQL, cryogenic cooling and a novel hybrid cryogenic and MQL (CryoMQL) cooling technique are used for CNC milling of age hardened Inconel 718. The analysis indicated that using the proposed hybrid CryoMQL cooling/lubricating system can almost double the tool life and improves surface roughness by 18% resulting in significant improvement in machinability of Inconel 718.