Through-Tool Drilling with Supercritical CO2 Metal Working Fluids

Metal working fluids (MWFs) are designed to cool and lubricate manufacturing operations. This $1 billion industry has not changed much in decades and today has a number of problems, including an inability to meet new machining challenges (e.g., titanium machining in aerospace applications), Employee Health and Safety (EH&S) concerns, toxic waste disposal, and cost. Today’s MWFs represent a significant environmental issue, with millions of gallons of contaminated material being produced per year in the United States alone. Fusion Coolant Systems, Inc. is commercializing a radically different system to replace conventional MWFs. Proposed is a new class of MWFs that is based on a high pressure solution of lubricants dissolved in supercritical carbon dioxide. These new MWFs, called CHiP Lubes (Cryogenic High Pressure Lubricants), have been shown to provide better cooling and higher lubricity than existing MWFs in several metalworking applications. Additionally, these MWFs have a much lower environmental footprint and lower overall system costs than current MWFs, and also eliminate health risks to workers arising from chemicals and microorganisms in today’s MWFs. They can be applied successfully in manufacturing where so-called “minimum quantity lubricants” cannot be applied and have a lower environmental footprint. The project already has attracted considerable commercial interest from industry partners. Numerous research obstacles must first be addressed, however, to allow the application of CHiP Lubes to a wider set of operations. The objective of this SBIR project is to develop the CHiP Lube system for deep-hole drilling. Whereas CHiP Lubes have been successfully demonstrated in simple, single-point turning applications, there is little understanding of how these innovative MWFs will perform in deep-hole drilling applications. A “through-tool” delivery of CHiP Lubes is necessary for this and has not yet been accomplished. The research is high-risk as CHiP Lubes will not have the same chip clearing efficiency as today’s MWFs (at a given pressure) because they are delivered in a carrier gas that is compressible, whereas liquid MWFs are not compressible. This will create challenges of delivering the fluid economically and there is some chance, even at supercritical pressures, that the system will not work. If the CHiP Lubes can be made to work through the research proposed in Phase I, however, it will be possible to remove a significant toxic waste stream from the environment, improve worker health and safety, and increase the profitability and competitiveness of the American manufacturing sector.