QMT News: April 2011
Guide to measuring surfaces published
The BSI has published a guide to the measurement and characterisation of surface topography whose principal author was National Physical Laboratory's Prof Richard Leach. The NPL also published an NPL guide on the measurement of rough surfaces using interferometry (relevant to other optical techniques).

BS 1134:2010 Assessment of surface texture
Often the surface of a work piece appears flat and smooth to the human eye. By running a finger across the surface it can feel smooth, but examining this surface under a magnifying device reveals a complex structure, which can be the result of factors such as material structure and paint on the surface, as well as the manufacturing processes to which the surface has been subjected.

A product's surface texture often affects its performance, quality and service life. It is critical in machine processing, as in many other disciplines, to evaluate and control the surface characteristics of many products. To control surface texture, it first has to be measured.

Measuring during the manufacturing cycle can influence decisions taken on machining systems and processes. This allows them to be controlled and optimised, thereby improving the product. Measuring surface texture at the end of the cycle helps engineers to form an opinion about the components' performance capability.

This British Standard gives guidance on the measurement of surface texture using a stylus instrument. This standard describes the way in which measurements can be taken and how to interpret the results. The guide also gives recommendations for the use of comparison specimens.

The measurement of rough surface topography using coherence scanning interferometry
The purpose of this guide is to describe good practice for the measurement and characterisation of rough surface topography using coherence scanning interferometry (commonly referred to as vertical scanning white light interferometry).

This guide is aimed at users of coherence scanning interferometry for the optical measurement of surface texture within production and research environments. The general guidelines described herein can be applied to the measurement of rough surfaces exhibiting different types of surface topography.

For the purpose of this guide, the definition of a rough surface is one that has features with heights ranging from approximately 10 nm to less than 100 µm.

www.npl.co.uk/news/measuring-surfaces

 

  
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