An Average Wavelength Parameter for Surface Metrology

Abstract

The new International Standard for the assessment of surface texture is based on the Arithmetic Average Height Index R_a. This parameter, although extremely valuable for quality control in manufacture, takes little or no account of the openness or closeness of the texture. Recently an additional parameter, the Average Wavelength Λ_a has been defined which is wavelength conscious and which supplements the information given by R_a. This paper shows how this new parameter can be derived and measured, and gives some practical examples of the application to surface texture measurement.