Systematic selection and evaluation of relevant surface roughness parameters for the characterisation of the innovative RPM-Synchronous Grinding process

Katharina Newrkla, Thomas Spenger, Ulrike Cihak-Bayr*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


The key to high performances and long lifetimes of machine components in lubricated contacts is often the surface topography. Its characteristics can be derived in numerous ways from 3D topography measurements, but these procedures do not follow any existing standards, resulting in limited comparability. In this work, we present a new, universally applicable workflow to reveal the most significant roughness parameters for a comprehensive description of differences in surface topographies. This workflow, based on principal component analysis (PCA), offers a standardization of parameter selection. It is applied to RPM-Synchronous Grinding (RSG), a novel grinding process that enables the production of non-circular geometries without an oscillating movement. To increase trust in this new technique, knowledge on how the process parameters affect the surface topography is required. Numerous statistical roughness parameters were derived from 3D confocal light microscopy as well as 2D tactile measurements on each ground workpiece. We apply the proposed workflow and find that, for the selected RSG parameter variations, Rq is the most relevant roughness parameter to capture changes in the surface topography. The 100 % fused white aluminum oxide grinding wheel, opposite grinding direction, and a low specific material removal rate result in the smoothest surfaces. A high degree of usage of the grinding wheel leads to higher Rq values, but there is a trend to reach a plateau value. The RSG machined workpieces are compared to conventionally ground and shortly run camshafts. The camshafts have Rq values in the range of the rougher RSG machined surfaces, but there are significant differences in the parameters Ssk, Sku, Sv and Vvv. Provided the number of workpieces is high enough for statstical analysis, we propose to apply our workflow for the selection of the most relevant roughness parameters to describe the differences between surfaces obtained by different machining parameters and processes.
Original languageEnglish
Article number015022
Number of pages18
JournalSurface Topography: Metrology and Properties
Issue number1
Early online date11 Feb 2021
Publication statusPublished - 1 Mar 2021


  • grinding
  • principal component analysis
  • RPM-Synchronous Grinding (RSG)
  • statistical roughness parameter
  • surface topography

ASJC Scopus subject areas

  • Instrumentation
  • Materials Chemistry
  • Surfaces, Coatings and Films
  • Process Chemistry and Technology

Fields of Expertise

  • Mobility & Production


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