The results of surface texture measurements obtained with the stylus equipment, white light interferometer and confocal profilometer of the same samples were compared. Machined isotropic and anisotropic surfaces, of symmetric and asymmetric ordinate distribution were measured. Forms were removed using polynomials. Sampling intervals and measuring areas during computations of parameters were the same. Discrepancies between the results obtained with various methods were observed and discussed. It was found that errors of surface texture measurement with the optical methods depend on the type of surface topography.
This work is focused on the issue of non-measured points – one of the most important problems in surface texture measurements using optical methods. The fundamental aim of this research is to analyse errors of surface texture measurements caused by the presence of non-measured points. This study is divided into two parts. In the first part, circles with non-measured points were artificially created on peak portions of measured surfaces. In the second part – the results of measurement by a Talysurf CCI Lite interferometer were analysed. A measurement area of 3.3 × 3.3 mm contained 1024 × 1024 points. The measurements were performed with different intensity of light. Changes of parameters regarding the analysed errors depended on a surface type. The following parameters are susceptible to errors: skewness Ssk, areal material ratio Smr, as well as the following feature parameters: Spd, Sda, Sdv, Sha and Shv. Inaccuracies of measurement in valley parts of two-process textures led usually to larger errors of parameter computations compared with deviations in peak portions.