Traceability for contact probe and stylus instrument measurements

A high proportion of component failures, such as in wind turbines, fuel injection systems and roller bearings, begin at the surface of materials, due to discontinuities or deterioration. Accurate measurement of surface roughness and form is, therefore, a vital aspect of quality control, that’s measured using coordinate-measuring machines (CMMs). As industry demands higher accuracy and lower uncertainties, faster CMMs are needed, with well-calibrated dynamic performance. This leads to raised requirements for traceable standards for surface roughness measurement devices, as well as for better calibration services for CMM probe dynamic performance.

This project has investigated new standards and artefacts, and established routes to SI units, aiming for cost-effective measurement capabilities with uncertainties down to 10 nm to 100 nm. The potential for applying portable displacement generators to calibrate stylus instruments beyond current ISO standards was investigated; noise reduction methods and novel investigatory methods developed; and outputs promoted to standards bodies.

Improved calibration of form and surface finish standards will help manufacturers obtain traceable, reliable measurements, leading to finer manufacturing tolerances.