TPT November 2007

Technology Update

cycle-time and improve efficiencies for fabricating aircraft duct components with complex shapes. Tubular parts with multiple bends are now fabricated in a single machine stage, eliminating a manually- controlled hydraulic bending process that could take a week or more. Senior Aerospace SSP makes ducting components for many of the world’s leading aircraft manufacturers, for applications such as engine exhaust gas recirculation, de-icing systems, and air conditioning. Most of the tubing parts are fabricated in small batches from exotic materials such as 625 and 718 Inconel, and titanium. Because of the space restrictions on most aircraft, parts often have complex 3D shapes with closely-spaced bends. Fabricating these using Senior Aerospace SSP’s manually- controlled hydraulic bending machinery typically involved a start-stop process, with bends made one at a time. This involved fitting the tooling and setting the machine up for each bend. Bent parts would then be sent off for cleaning, and the exercise repeated for the next bend one or more days later. This meant that for parts with

three or four bends, a complete fabrication cycle could often last a week or more. To improve productivity, Senior Aerospace SSP invested in an all-electric tube bending machine from Unison, for tubing sizes up to 4" (100mm) diameter. The bending axes on this machine are based on software- controlled servomotors. Tool settings for tube parts are stored in software, allowing the machine to be setup and a complete sequence of bends to be made in a single continuous process. Several of the parts being made have such closely spaced bends that the machine is programmed to accommodate specially- designed compound tooling that grips the previous bend, because the straight sections between bends are too short for conventional clamping tools. The machine also has the ability to stack as many as four bending tools at once onto the bending head. This saves considerable setup time by allowing a variety of jobs to be run without having to make a new setup. Tubing parts with multiple bends – which are typically fabricated in small batches of

up to 20 with production cycle times ranging from several days to two weeks – are now almost invariably produced in a single shift. Unlike the previous manually controlled bending process, these batches are also typically produced without any scrap, as the machine’s closed-loop control maintains axis settings to a very fine resolution, regardless of variations in operating conditions such as temperature. “The Unison machine has allowed us to trim days off the normal fabrication times for many of the complex tubing parts we produce, as well as eliminating intermediate cleaning processes,” says Mr Thomas Marshall, manufacturing engineer at Senior Aerospace SSP in Burbank. “It’s playing a valuable role in improving the productivity and flexibility of one of our key component production processes.” Unison – UK Fax : +44 1723 582379 Email : enquiries@unisonltd.com Website : www.unisonltd.com Horn Machine Tools (US agent) – USA Fax : +1 559 431 4431 Email : hmt@sierratel.com Website : www.hornmachinetools.com

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N ovember /D ecember 2007