Tube-bending technology deployed for aerospace applications

Paul Boughton

Unison has won an order for tube bending machinery from the precision aerospace engineering company, Supercraft. The machinery will help Supercraft to expand operations at its new manufacturing facility in Brough, UK, in preparation for contracts recently secured from major aerospace customers. It will also provide the software flexibility needed to enhance productivity of specialist low volume parts through use of ‘closed-loop’ manufacturing techniques.

The order calls for two Unison machines. Supercraft wanted another Evbend 1000 low-cost CNC tube bender – a novel machine that minimises the costs of producing small-batch high value parts by means of manually powered tube feed, rotation and bending, but with smart CNC-controlled braking on these axes to ensure precision. The second machine is a 30mm model from the Breeze family of all-electric tube benders. The Evbend machine was installed at Supercraft’s Brough facility in December 2014; the 30mm Breeze is scheduled for delivery in Q1 2015.

Supercraft is a leading manufacturer of precision components and assemblies for military and civil aerospace companies – its facility in Brough specialises in the production of pipes and ducting for aircraft wings. The company makes extensive use of CNC tube and pipe bending technology and is capable of fabricating parts involving complex precision bends in tubes up to 100mm in diameter. Automated bending machines in the workshop at Brough are networked to a central CAD/CAM resource which includes an advanced laser-based coordinate measuring machine (CMM).

The CMM uses non tactile laser measurement techniques to build detailed and highly accurate 3D computer models of bent parts. Measurements are typically taken from pre-production parts for process verification, with any necessary correction data being fed back to the bending machines. This efficient closed-loop manufacturing system helps Supercraft to meet the exceptionally high quality standards demanded of aerospace suppliers, and to minimise the time that it takes to commence volume production of parts. Measurements can also be acquired from customer-supplied parts and used for reverse engineering purposes. Customers are therefore free to specify their requirements in a wide variety of forms, including drawings, CAD models, files containing XYZ tube bending machine data, and master parts.

Supercraft initially sought a replacement for a first-generation Evbend 1000 tube bender that it had used successfully for about 30 years. Originally developed by a tube manipulation specialist to help companies reduce the cost of producing low volume precision parts, the Evbend machine has proved particularly popular in aerospace and motor racing industries. Unison acquired the manufacturing and design rights to Evbend and developed a new-generation version of the tube bender in 2014.

According to Supercraft’s general manager, Owen Sexon, “The Evbend machine provides a very cost-effective means of fabricating precision parts made in low volumes. We typically use it for bending five to 10 millimetre tubes with a half-millimetre wall thickness – many of the smaller diameter parts that we produce involve complex bend sequences, and very small batch sizes – often in the order of just six to eight. Setting up one of our large existing machines for these types of needs is simply not economic.”
However, until now, Evbend tube benders have essentially been standalone machines – the original controller had very limited I/O facilities – so when Supercraft sought a replacement it looked at a number of competitive machines that could be networked to its CMM. While investigating its options, Supercraft became aware that Unison has developed a new version of the Evbend 1000, incorporating a powerful HMI and controller software designed expressly for ease of integration into factory networks.
As Sexon says, “We are really impressed by the quality, breadth and ease-of-use of Unison’s software. The fact that Unison was prepared to develop custom software and take responsibility for interfacing the new Evbend machine to our CMM made it an obvious purchase choice. For the first time, we are able to close the loop between inspection and bending on small batch size tasks as well as higher volume production. Eliminating what is often a highly iterative process will help us to improve productivity of prototypes and specialist parts significantly.”

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