Thermal design and time-dependent dimensional drift behaviour of sensors, materials and structures

Advanced industries such as aerospace and ICT rely on precision engineering and sophisticated production equipment to manufacture complex and miniaturised components and products. With precision engineering demanding ever-higher accuracies for industrial production and measurement equipment, temperature effects and time-dependent drift become a serious limitation to system performance.  

This project developed the metrological tools and methods to support optimisation of the thermal stability of ultra-precision engineering measurement and production tools over timescales of weeks to months. The project addressed material and joint properties (aging, thermal dilatation, indentation creep); temperature sensors (thermocouples, self-calibrating sensors with fixed points from alloys); thermal modelling and control (development of thermally-insensitive machine designs) and developed:

• A picodrift interferometer for assessing instrument dimensional stability capable of detecting at the nanometre level over days.
• Novel procedures to calibrate the displacement of high-temperature nano-indentation equipment at elevated temperatures.
• Reliable and stable temperature measurement tools and sensors with uncertainties at the millikelvin level.
• Models for thermal-induced deformations of instrument structure to support the design of stable instrumentation.
• A prototype measurement system for ambient temperatures based on highly-accurate thermocouples and precise temperature control. This system enables the performance of measurement instrumentation to be assessed under temperature fluctuations in ambient conditions. 

The tools and methods developed in the project are all publicly available and some outputs are already in use. For example, the prototype measurement system for ambient temperatures has been used by a manufacturer to improve the performance of its instrument for ultra-precision dimensional measurements and a license to commercialise the prototype has been granted to a manufacturer in Germany.