Optimising Assembly Processes Through In-situ Measurement
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Optimising Assembly Processes Through In-situ Measurement

The MTC worked with Rolls-Royce to develop a methodology for measuring bolt clamping load in-situ
within a restricted geometry environment.


  • Assembly of a critical bolted joint within a Rolls-Royce engine is currently reliable, but there were opportunities to improve and optimise the design for the fitter
  • Future product designs are likely to require ever increasing clamping load capability, driving the requirement for improved and more efficient methods
  • The bolted joint is located within a restricted and difficult-to-access geometry, severely limiting the options for in-situ measurement


  • Identified the use of ultrasonic technology to enable in-situ measurement of bolt clamping load
  • Developed a functional tooling prototype to implement ultrasonic measurement capability within an existing tooling footprint
  • Designed and manufactured a suite of test hardware to prove the technology and the process
  • Conducted a detailed series of trials to prove performance, collect relevant parameters, and enable practical usage of technique on development engine build
Can I pass on my congratulations to the Rolls-Royce/MTC team… it’s great to have a project go from early ideas and concepts and then see it all the way through to actually being used to build an engine.
Alan Pardoe, Partnership Manager, Rolls-Royce


  • Creation of a bolt design ensuring correct ultrasonic functionality
  • Development of a functional tooling prototype that enables ultrasonic measurement of bolt clamping
    load to within +/- 5kN
  • Creation of representative ‘engine core’ test hardware that enables a full simulation of the bolted joint
    assembly process
  • Test bench’ hardware that enables single-bolt testing for ongoing calibration
  • Ongoing support to determine specific material and geometry factors for development engine bolt designs


  • Significant improvement in accuracy of assembly clamping load measurement, enabling significant reduction in reserve factors
  • Implementation of a measurement system that directly displays bolt clamping load during operation; and enables straightforward data collection for improved traceability
  • Implementation within existing tooling means minimal impact to current assembly process
  • Provision of test hardware to enable demonstration of process, operator training, and future testing using
    new bolt materials
  • Provision of measurement data and corresponding statistical analysis in order to support faster technology development/deployment
  • Functional tooling prototype that has been successfully used in assembly of engine demonstrator
The combined Rolls-Royce and MTC team has produced an effective and efficient methodology which will provide many benefits to industry.
Geraint Prisk, Manufacturing Engineering Lead UltraFan, Rolls Royce