Cooling and Lubrication Technologies for Machining Advanced Alloys
: (Alternative Format Thesis)

  • Andrea De Bartolomeis

Student thesis: Doctoral ThesisPhD


High temperatures generated during machining processes reduce productivity, cause increased cutting tool wear and damage the machined surfaces. Cutting fluids are used to reduce the cutting temperature, provide lubrication, guarantee chip flushing and chemically protect the machined surface. In the industrial practice, flood cooling is the technique of immersing the entire cutting zone with cutting fluids that provides significant increases in cutting tool life and improved surface finish.
However, cutting fluids are expensive and pollutants. Machining without these fluids, also known as dry machining, can be implemented for easy-to-cut materials. This is not the case with difficult-to-cut alloys that still require an abundance of cutting fluids to be machined. Today, the machining of Inconel 718 and Ti-6Al-4V represent two of the greatest challenges faced by the machining industry. More than 50% of the modern aeroengines are made from Inconel 718 and the machining of those advanced alloys using flood cooling conditions is not environmentally conscious nor economically sustainable.
To machine Inconel 718 and Ti-6Al-4V alloys, as an alternative to flood cooling, Minimum Quantity Lubrication (MQL) has been shown to be most promising. Despite providing significant improvements when compared with other alternatives, machining performance with MQL is still far from the advantages provided by cutting fluids in flood cooling conditions.
The research reported in this thesis explores novel nozzle designs and systems, investigating the feasibility of applying EHDA MQL in milling Inconel 718 and Ti-6Al-4V. EHDA MQL is a novel technique that can improve MQL performance and eliminate the use of water-based cutting fluids. The novelty is the development of a new MQL system called Electrohydrodynamic Atomization for Minimum Quantity Lubrication (EHDA MQL) that provides charged oil based on a two-electrode configuration and testing it on the machining of Inconel 718 and Ti-6Al-4V.
Results show that this new technology for EHDA MQL can provide an extension of 52% in tool life when compared with conventional MQL in end milling Inconel 718. The extension in tool life observed when machining Ti-6Al-4V was over 2200% in comparison with conventional flood cooling application. The results showed that tool life is about 170 min when high-speed machining Ti-6Al-4V at 120 m/min. This poses a milestone in the removal of cutting fluids from manufacturing. The research revealed that EHDA MQL has provided significant advantages in the case of Inconel 718 and Ti-6Al-4V over conventional MQL.
Date of Award16 Jun 2021
Original languageEnglish
Awarding Institution
  • University of Bath
SupervisorAlborz Shokrani Chaharsooghi (Supervisor) & Stephen Newman (Supervisor)


  • Machining
  • MQL
  • Inconel 718
  • Milling

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