Application of function-oriented roughness parameters using confocal microscopy

Optical measuring instruments are widely used for the functional characterization of surface topography. However, due to the interaction of the surface with the incident light, effects occur that can influence the measured topography height values and the obtained surface texture parameters. Therefore, we describe a systematic investigation of the influences of optical surface topography measurement on the acquisition of function-oriented roughness parameters. The same evaluation areas of varying cylinder liners which represent a typical application of function-oriented roughness parameters were measured with a confocal microscope and a stylus instrument. Functional surface texture parameters as given in the standards ISO 13565-2, ISO 13565-3 and ISO 25178-2 were evaluated for both measurement methods and compared. The transmission of specific surface features was described and a correlation analysis for the surface topographies obtained with the different measurement methods and their resulting functional roughness parameters was carried out.