Bolton-based Silcoms supplies the aerospace industry with nickel alloy, titanium, stainless steel and aluminium engine ring components and assemblies, including seals, shrouds, segments and casings.
The company was awarded an additional contract in 2018 to supply a complex rotating fan seal for a large civil aircraft engine programme, which prompted the need for additional capacity. Managing director Jim Hill took the opportunity to develop a new process route that would speed production of the rotational titanium parts, while maintaining the tight tolerances needed.
The new method of manufacture now hinges on the use of a Hermle C50 UMT five-axis machining centre fitted with a torque table for carrying out in-cycle turning operations. Supplied by Kingsbury, the machine performs three operations in two set-ups that previously required five operations on three different machines. As a result, floor-to-floor time has been reduced, while fewer set-ups mean that the risk of accumulative tolerance error is minimal.
Produced from a titanium forging, the 1015 mm diameter fan seal has to be turned to a final wall thickness of 3 mm. Here, it is crucial to control dimensional accuracy and avoid distortion. After a number of preparatory machining stages, the Hermle five-axis machining centre completes the next five operations in two set-ups over 20 hours. Semi-finish and finish turning have been compressed into one operation on each side. During the second clamping on the Hermle, turned and milled features are completed. Critical dimensional features are held to ±20 µm over the full diameter of the part.
Says Hill: “Consolidating turning and milling on one machine has significant benefits. Apart from a reduction in component handling and an improvement in accuracy, it cuts the lead-time for converting a titanium forging into a finished seal, and reduces the total number of tools we need.”
For further information www.kingsburyuk.com