Flex tooling for gas turbine components
High market demand for gas-engine turbines in the aircraft industry has driven the need for more efficient, reliable and flexible manufacturing technologies for producing turbine components. The EU-funded project 'Unconventional (advanced) manufacturing processes for gas-engine turbine components' (ADMAP-GAS) developed two new, advanced systems in this respect. It focused on improved ways to manufacture 'fir tree' profiles that connect rotating blades and discs (blisks) in engines. ADMAP-GAS evaluated abrasive water jet cutting (AWJC) and high-speed wire electrical discharge machining (HS-WEDM) to improve overall machining operations. No special tool had to be manufactured and tool wear had no influence on the workpiece performance. These new unconventional processes also helped to overcome machining challenges posed by the thermal and mechanical hardiness of nickel-based superalloys. Scientists showed that both manufacturing technologies hold great promise for machining fir tree geometry profiles. Both processes improved material removal rates in combination with high form accuracy and surface quality. Compared to broaching, they allowed very flexible production of different profile geometries. The developed AWJC process proved to be suitable for roughing cuts, which require a very economic technology to process hard-to-machine alloys. The process monitoring system, the multi-axis cutting head and the new developed nozzle geometry were all developed within ADMAP-GAS. Furthermore, the HS-WEDM process also proved to be a serious alternative to broaching, especially in terms of surface fatigue behaviour. Through optimising technology, scientists improved cutting rates and achieved very good surface integrities (minimal surface layer and contamination, and absence of cracks). Failure risks of engine discs decreased through the developed process monitoring systems. A life-cycle cost analysis showed a 25 % decrease in machining costs for producing a fir tree profile using one of the developed processes. Furthermore, both showed a large decrease in the environmental impact of machining processes, as much as 60 %, through reduced energy consumption. Beyond the aeronautics industry, both technologies also offer much promise for the automotive industry.
Keywords
Turbine components, machining, broaching, aeronautics, gas-engine turbine, manufacturing technologies, fir tree, blisk, water jet cutting, electrical discharge machining, surface fatigue behaviour
