Reduction in Errors in Roughness Evaluation with an AccurateDefinition of the S-L Surface – Przemysław Podulka , Wojciech Macek , Ricardo Branco and Reza Masoudi Nejad

Abstract:

Characterization of surface topography, roughly divided into measurement and data
analysis, can be valuable in the process of validation of the tribological performance of machined
parts. Surface topography, especially the roughness, can respond straightly to the machining process
and, in some cases, is defined as a fingerprint of the manufacturing. When considering the high
precision of surface topography studies, the definition of both S-surface and L-surface can drive
many errors that influence the analysis of the accuracy of the manufacturing process. Even if precise
measuring equipment (device and method) is provided but received data are processed erroneously,
the precision is still lost. From that matter, the precise definition of the S-L surface can be valuable
in the roughness evaluation allowing a reduction in the rejection of properly made parts. In this
paper, it was proposed how to select an appropriate procedure for the removal of the L- and S components
from the raw measured data. Various types of surface topographies were considered,
e.g., plateau-honed (some with burnished oil pockets), turned, milled, ground, laser-textured, ceramic,
composite, and, generally, isotropic. They were measured with different (stylus and optical) methods,
respectively, and parameters from the ISO 25178 standard were also taken into consideration. It
was found that commonly used and available commercial software methods can be valuable and
especially helpful in the precise definition of the S-L surface; respectively, its usage requires an
appropriate response (knowledge) from the users.