Surface Topography Modelling for Reduced Friction

Marko Sedlaček,Luis Miguel Silva Vilhena,Jože Vižintin,Bojan Podgornik

doi:10.5545/sv-jme.2010.140

Marko Sedlaček, Luis Miguel Silva Vilhena + Show 2 more

Open Access

https://doi.org/10.5545/sv-jme.2010.140

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Abstract

The aim of the present research was to investigate the possibility to design contact surfaces with reduced friction using surface roughness and topography analysis. For this purpose, different 100Cr6 plate samples with different surface topography were prepared. Using different grades and combinations of grinding and polishing samples with similar Ra values, but different Rku and Rsk values were prepared. To evaluate influence of roughness parameters on friction and wear, dry and lubricated pin-on-disc tests were carried out under different contact conditions. Test results show that surfaces with high Rku and negative Rsk values results in reduced friction. To investigate the effect of surface topography on surface roughness parameters and consequently on friction, real roughness profiles were virtually altered to achieve virtually textured surfaces. Using NIST SMATS softgauge for calculation of surface roughness parameters, virtually altered roughness profiles were investigated in terms of texture size, shape and spacing, and their influence on surface roughness parameters, especially on skewness and kurtosis. Lower diameter, higher spacing and wedgeshaped dimples were found to reflect in higher Rku and more negative Rsk parameters, which should lead to lower friction.

Highlights

Controlling the friction is becoming more and more important because of constant demands for improved reliability and effectiveness of mechanical parts and especially reduction in frictional loses
A possible way to design surface texturing parameters, which would result in contact surfaces with lower friction, is by treating surface texturing as a controlled roughness
Under dry sliding high wear rates and change in surface topography blurs the effect of surface roughness on friction

Summary

Introduction

Controlling the friction is becoming more and more important because of constant demands for improved reliability and effectiveness of mechanical parts and especially reduction in frictional loses. A possible way to design surface texturing parameters, which would result in contact surfaces with lower friction, is by treating surface texturing as a controlled roughness. It was observed that parameters Rk, Rpk and Rvk tend to have influence on coefficient of friction [16].Parameters Rk, Rpk and Rvkare based on the bearing ration curve (AbbottFirestone Curve) and are defined by the standard ISO13565-2. Core peak-to-valley height (Rk) give a numerical summary of information contained in the bearing ratio curve based on a division of the curve into three regions. When two surfaces rub together, the peak region gets usually worn away; the core region bears the load and has influence on the life of the product and valley region which acts as a lubricant reservoir

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