Explanation of Lubrication Behavior by means of Oil Film Measurement on Rolled Sheet Surface Measured by Fluorescence Method

摘要

The photographs of workpiece surface illuminated with the UV light after rolling are taken by means of a fluorescence microscope with a camera. The workpieces having a smooth surface and a random rough surface are used in the experiments. The rolling tests are carried out changing rolling speed and viscosity of lubricant. The rolling oil containing some amount of fluorescence dye is used as a lubricant. The bright area is characterized by the lubricant pocket and the dark area by the asperity contact. From these photographs, the lubrication mechanism can be understood qualitatively. From the relationship between surface roughnesses of workpiece and roll, and inlet oil film thickness, the lubrication regime can be classified into the four regions which are the hydrodynamic lubrication, the hydrodynamic-boundary lubrication, the hydrodynamic-hydrostatic-boundary lubrication and the hydrostatic-boundary lubrication.Moreover, the visual light intensity produced by the fluorescence phenomena is measured by means of a fluorescence microscope with a ultra high sensitive CCD camera and an image processor From the relationship between light intensity and oil film thickness, the oil film thickness distribution on the workpiece surface can be measured quantitatively.