FT Gearing achieved Nadcap approval for EDM machining after bringing the process back in-house on three new Makino machines.
Aldershot-based FT Gearing supplies the global defence and aerospace sectors with gears, miniature gearboxes and safety critical components for wing surface actuators, engine controls, instrumentation and fuel pumps. Many years ago, the manufacturer tried broaching the bore profiles in steel worm shafts to transmit the drive to thrust reversers, but the length-to-diameter ratios were too high and the tools broke frequently.
So the company put the work out to a wire-type EDM (electric discharge machining) subcontractor in the Midlands. The service was expensive, partly because the firm needed to have Nadcap approval, a requirement of primes such as Boeing and Airbus as well as tier-one aerospace companies, all of which FT Gearing supplies.
The situation has been turned on its head following the arrival over an 18-month period of three Makino wire EDM machines at an FT Gearing satellite facility close to the company’s main factory. The machines were supplied by NCMT, UK agent for the Japanese machine builder.
Within six months of the first machine arriving, FT had gained Nadcap approval, while the latest EDM machine installed mid-2017 provides capacity for internal development projects and offering a subcontract wire EDM service.
Managing director Graham Fitzgerald, who started the business with his father Des in 1978, commented, “We chose U3 wire eroders from Makino after we employed a skilled EDM machinist that has a lot of experience operating machines of the same make and rates them highly.
“He says that ISO programming on the Fanuc-based control is far easier than on some other EDM machines that employ two languages, macros are simpler to create and operations like rotation and mirror imaging are straightforward.
“From my perspective, quicker programming leads to higher productivity. The machines are also reliable and their build quality means they sit well alongside top-end, 4- and 5-axis machining centres in our Unit 19, which we recently opened.”
The Makino’s advanced technology is brought to bear on FT Gearing’s S106 and S82 aircraft steel worm shafts to produce bores of square, double-D, hexagonal and other shapes that provide the drive to the reverse thrust flap. Dimensional tolerance is to within 10 microns and cycle times range from one to three hours.
There is spare capacity to wire-EDM other components as well, such as internal gears, splines and keyways. Mr Elwick said, “Usually they require special gear cutters that can take up to 16 weeks to be delivered, but they can be put straight onto a Makino U3 without delay. Although machining takes a little longer, parts can be processed in their hardened state, so distortion and potential rework are avoided.”