Wieslaw Grabon

Variability of areal surface topography parameters due to the change in surface orientation to measurement direction

Several random surface topographies were analyzed. They were measured by optical (Talysurf CCI Lite) method. They represent one- and two-process anisotropic and isotropic surfaces. These surfaces were rotated of ± 1° and ± 2° by two methods: on the plane table (before measurement) and virtually (after measurement) using the software TalyMap Gold. After each measurement or surface rotation, each surface was levelled. Then, the forms were removed using polynomial of the 3rd degree. Areal surface topography parameters from standard ISO 25178 were calculated. The relative deviations of parameters were determined. The tendency of surface topography changes characteristic to various surface types were analyzed. It was found that change in orientation to the measurement direction of both isotropic and anisotropic surfaces could be substantial source of the measurement uncertainty. Functional parameter Smr and also feature parameters Sda, Sha, Sdv, Shv, and Spd are the mostly sensitive on measurement orientation. Statistical amplitude parameters Sa and Sq are more stable than parameters describing maximum surface height, like Sz, Sp, and Sv. The effect of surface orientation to measurement direction on values of functional parameters from V group was small. It was shown that changes of Sdq, Sdr, and Spc parameters describing hybrid properties due to surface rotation before measurement were smaller than those caused by change in surface orientation after measurement.

Problems of surface topography with oil pockets analysis

The present paper presents method of description of two-process surfaces of random (load-bearing plateau structure) and deterministic (oil pockets) character on the basis of the probabilistic approach of material ratio curve. Examples of this method usage for textured surfaces are shown. The other application of material ratio curve for estimation of pit-area ratio of textured surfaces is discussed. Distortion of surface topography with oil pockets measurement by improper selection of areal reference plane is taken into consideration.

A study of variations of areal parameters on machined surfaces

This paper presents an analysis of variations of areal parameters on surfaces. Textures were measured using stylus equipment. After form removal, parameters from the ISO 25178 standard were computed using TalyMap Gold software. Then measured areas of these topographies were divided into smaller sub-areas, for which the parameters were calculated again. Relative deviations between parameters from measured areas and sub-areas were calculated as well as the coefficients of variation of parameters in sub-areas. The tendencies of parameter variations for various types of measured surfaces were studied. Parameters that were stable for surfaces and sensitive to surface irregularities were selected.