Modern gas turbine materials are chosen primarily for their ability to withstand the extreme environment in which they operate and consequently the strength, stiffness and corrosion resistance of such materials are consistently at the very upper end of capability. Typically, however, materials with such desirable properties are notoriously difficult to machine, creating a significant challenge in developing and applying the optimum Machining Technology for production of engine components.
In order to achieve the precision assembly requirements demanded by a gas turbine engine, most engine components will require some form of machining to be undertaken. It is imperative that the machining processes selected and developed for production are fully capable of delivering the surface finish and material properties demanded by exacting design criteria.
The availability of high-speed, multi-axis CNC machine tools, using advanced ceramic and intermetallic cutting materials, has resulted in machining processes which are highly efficient and offer substantial cost reduction and productivity opportunities for Rolls-Royce. One such example is the VIPER grinding process, developed by Rolls-Royce for use on their production machining centres, and capable of achieving extraordinary cutting rates that remove metal 5x faster than traditional turning techniques.
Alongside development of the core machining technique (e.g. milling, drilling, grinding, turning) advances are also being made with process monitoring, in-process measurement, cutting tool optimisation, improved cooling systems, fixturing and process modelling, all of which are crucial enabling elements that aid the improvement of cycle times and quality of the machined components.
Advanced machining technology