A method of optical roughness measurement on ultrafine metal surfaces

Abstract

In the article, an optical method is described to measure the surface roughness on ultrafine machined metal surfaces. The method is capable for measurement of surface roughness without mechanical contact, and without removing the work piece from the machine. The traditional stylus-type devices require direct physical contact, which leaves scratches on the parts, whereas this optical method leaves the parts untouched. It is important to mention in advance that the characteristic magnitude of the roughness has to be below the wavelength of the applied electromagnetic wave, since this assumption is taken strictly in consideration of our method. If we apply any diode laser which operates in the typical wavelength range of 0.6-1 μ m, in such a case the adequate average roughness is below 0.1 μ m, we may speak in this sense about ultrafine machining.