The liquid nitrogen as an environmentally safe coolant has been widely recognized in cryogenic machining, its function as a lubricant is plausible due to its chemical inertness, physical volatility and low viscosity. Since a reduced friction is a direct witness of the lubrication effect from a tribological viewpoint, this paper presents an evaluation of the apparent friction coefficient on the tool-chip interface in cryogenic cutting operations to prove and characterize the lubricity of LN2 in cryogenic machining. The cryogenic cutting technology used in this study is based on a cooling approach and liquid nitrogen delivery system which are intended to apply liquid nitrogen in well-controlled fine jets to selectively localized cutting zones and to penetrate liquid nitrogen to the tool-chip interface. It has been found that the apparent friction coefficient can be significantly reduced in cryogenic machining, depending on the approach of liquid nitrogen delivery.
Bibliographical noteFunding Information:
The authors wish to express their gratitude for the financial support of the cryogenic machining project by the National Science Foundation
(Grant No. DMI-9528710) and the Edison Materials Technology Center (Project No. CT-32), and for the joint partnership with Cineinnati-Milacron, General Motors-Delco Chassis, Tim-ken Company, Kennametal Inc., GE Aircraft Engines, BOC Group, Vortec Co., A.F.Leis Co., Enginetics Co., Abrasive-Form, Inc., and Gem City Engineering.
All Science Journal Classification (ASJC) codes
- Mechanics of Materials
- Mechanical Engineering