Mist Generation from High-Speed Grinding with Straight Oils

Abstract

High-speed grinding with plated-CBN wheels generally requires the use of straight oils as the metal removal fluid to obtain the required performance. Unfortunately, the combination of straight oils and high speeds results in high mist generation. In this study, several grinding oils were tested for both performance and misting characteristics. Oils were chosen to cover a range of viscosities, additives, and oil types. Two fluids were also tested with antimisting polymers and showed significant decreases in mist after polymer addition. The distribution of the mist droplet size was also measured, which gives information about the mist generation mechanism; centrifugally produced aerosols are in the 1-10 μ m range, while condensation aerosols are in the 0.1-1 μ m range. Oil performance, as indicated by the power and force monitors, showed little difference between the oils. However, mist generation was highly variable across the eight tested oils. The generation of centrifugal aerosols was related to the viscosity and the surface tension of the fluid, while the generation of condensation aerosols was related to the Noack volatility and the flash point of the fluid. Higher fluid flows led to increased centrifugal aerosols and decreased condensation aerosols.

KEY WORDS:

• Metalworking Fluids
• Grinding Oils
• Environment and Safety
• Mist

ACKNOWLEDGEMENTS

We would like to thank Don Chester of GM R&D for his assistance with the experiments, and Mike Bilbrey, Blair Lorimer and Aleks Filipovic of PT as well as the Powertrain Bay City Plant for supporting the study. Special thanks to Todd Gearig of Owens Community College for operating the grinder. Finally, we would like to thank Liwen Wei of Shrieve Oil, Paul Michael of Benz Oil, Eric Sutherland of Chrysan, and Scott Prickett and Kathy Coughenour of Quaker for their assistance.

Review led by Jerry Byers

Notes

*Information provided by fluid supplier.

*3-Cam grinding test.

*Three-cam test and two-cam test results shown, respectively.

**Difference between total aerosol and fluid-only aerosol.