Spectral analysis for the effects of stylus tipcurvature on measuring isotropic rough surfaces

Abstract

Spectral analysis and computer simulation are adopted toinvestigate the tracing of three-dimensional isotropic rough surfaceswith a spherical tipped stylus. It is shown that the measuring errorstrongly depends on the ratio of the radius r of the stylus tip tothe root-mean-square (rms) roughness σ and on the ratio ofthe 1/e correlation distance b to the rms roughness σ.By using the concept of critical wavenumber, the profile and surfacespectral densities of a measured surface can be estimated. Also, aformula is developed to estimate the error of the rms height.