Explanation of lubrication behavior by means of oil film measurement on rolled sheet surface measured by fluorescence method

The photographs of workpiece surface illuminated with the UV light after ro lling are taken by means of a fluorescence microscope with a camera. The wo rkpieces 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 fluoresce nce dye is used as a lubricant. The bright area is characterized by the lub ricant pocket and the dark area by the asperity contact. From these photogr aphs, the lubrication mechanism can be understood qualitatively. From the r elationship between surface roughnesses of workpiece and roll, and inlet oi l film thickness, the lubrication regime can be classified into the four re gions which are the hydrodynamic lubrication, the hydrodynamic-boundary lub rication, the hydrodynamic-hydrostatic-boundary lubrication and the hydrost atic-boundary lubrication. Moreover, the visual light intensity produced by the fluorescence phenomena is measured by means of a fluorescence microscope with a ultra high sensit ive CCD camera and an image processor. From the relationship between light intensity and oil film thickness, the oil film thickness distribution on th e workpiece surface can be measured quantitatively.