Tube bending machine boosts production efficiency

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A Unison all-electric tube bending machine is helping Senior Aerospace SSP to dramatically reduce cycle times and improve efficiencies for fabricating complex aircraft duct components.

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 three-dimensional 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 required the machine to be tooled and set 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. For parts with three or four bends, a complete fabrication cycle could therefore 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 4inch/100mm diameter. The bending axes on this machine are based on software-controlled servomotors, with tool settings stored in software, allowing the machine to be set up and a complete sequence of bends 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.

Stacked tooling

The machine is also able to stack as many as four bending tools at once on the bending head. This saves considerable set-up time by allowing a variety of jobs to be run without having to make a new set-up.

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.

Thomas Marshall, Manufacturing Engineer at Senior Aerospace SSP in Burbank, comments: "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. It is playing a valuable role in improving the productivity and flexibility of one of our key component production processes."

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