Measurement of surface roughness using infrared scattering

Abstract

Non-contact measurement applied to in-process measurement of surface roughness is essential to engineering industries inasmuch as the function of a surface and its roughness are closely related. The measurement range of light-scattering techniques can be extended by using IR-light, e.g. γ = 10.6 μm. The experiments described in this paper illustrate the possibility of using light-scattering techniques to measure roughness on surfaces with an approximate R a < 4 μm, R a being the arithmetical mean deviation of the profile. The light-scattering techniques presented in this paper classify the specimens in the same manner as the stylus instrument.