NPL has recently completed a project to allow industry to benefit from the use of areal surface topography measurement to enhance a range of high-value products. The surface topography of a component part can have a profound effect on the function of the part. In tribology, it is the surface that influences such quantities as friction, wear and the lifetime of a component. In fluid dynamics, it is the surface that determines how fluids flow over a surface and affects such properties as aerodynamic lift, therefore, influencing efficiency and fuel consumption. And the list goes on – examples of surface-function relationships can be found in almost every manufacturing sector, both traditional and high-tech. To control surface topography, and hence the function of a component, it must be measured and useful parameters extracted from the measurement data.
The recent NPL work involves:
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Developing an infrastructure to calibrate surface topography measuring instruments. This involves a unique box of artefacts to allow calibration of instrument parameters, coupled with a number of good practice guides and several journal articles. The work is now forming the basis of a new ISO standard that will allow instrument users to gain confidence in their measurements and set up appropriate quality control systems.
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Development of reference software to allow instrument users to test their software for areal surface texture parameters. Journal papers on this work have been submitted and a comparison of commercial software carried out. See website:
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Production of a number of NPL reports relating surface function or machining to areal surface texture parameters. This includes three open reports for Cranfield Precision (control of grinding for crankshaft manufacture), Loughborough University (control of copper plating on glass for new electronic applications) and Bradford University (investigating whether surface texture parameters can predict what stone age people used to eat from friction marks on tools). The outputs also included more work for UK industry which is currently restricted for commercial reasons.
Professor Richard Leach FInstP FIoN
Principal Research Scientist
Engineering Measurement Division
National Physical Laboratory
Hampton Road, Teddington
Middlesex TW11 0LW
Tel: +44 20 8943 6303
www.npl.co.uk