Electric tube bender selected for submarine work

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A state-of-the-art all-electric CNC tube bending machine from Unison is giving BAE Systems Submarine Solutions greater flexibility to fabricate the complex part shapes required while building the UK's Astute class nuclear-powered submarines.

Electric tube bender selected for submarine workA Unison all-electric CNC tube bender being used by BAE Systems Submarine Solutions at Barrow-in-Furness features both right- and left-handed bending capability. This enables long and complicated tubular part shapes to be produced very rapidly and in a single stage. For BAE Systems this is a critical advantage, as the boat building process must run to plan and many parts are produced to demand to satisfy the production schedule.

In some cases, such as when fabricating tubular shapes several metres in length, the new machine also enables BAE Systems to make parts from a single length of tubing, thereby avoiding the need to join tube sections. In addition to production speed advantages, this new capability also eliminates time-consuming and expensive X-ray and crack-detection testing stages that would otherwise be required to verify the integrity of welded joints for this high-reliability equipment.

The new 20mm machine has been purchased to increase the production capacity and flexibility of the pipe shop at the company's Barrow-in-Furness shipyard. It is being used alongside a number of hydraulic tube bending machines. As well as being the first right- and left-handed machine, the new equipment is also the shipbuilder's first 'all-electric' tube bender, with position control achieved via servomotor-based movement axes.

Restricted space

Fabricating highly complex tubular shapes is an everyday task for the pipe shop. In order to fit in all of the submarine's equipment, and maximise the free space available, small-bore piping and tubing services such as hydraulic lines are often shaped to fit into the free spaces available adjacent to panels and bulkheads. Consequently, tubular parts are often fabricated in batch sizes of just one.

The Unison tube bender is making it quicker to produce components, as programs are simply loaded from the design database, and bends are then made precisely by the servomotor movement axes with their closed-loop control mechanisms. No manual intervention or adjustments of any kind are required. If the tooling is already on the machine, the set-up operation is achieved in around 15 minutes or less. This is typically at least twice as fast as the set-up process for the company's hydraulic bending machines.

A power consumption reduction is another intrinsic advantage of the Unison bender. As there are no hydraulic pumps continuously running, significant electrical current is only drawn when the machine is making a bend, so energy consumption is reduced substantially.

BAE Systems chose to purchase a machine from Unison because of the company's UK location and its reputation — Unison pioneered the all-electric concept and has produced machines for some of the world's most demanding applications, including naval shipbuilders and aerospace companies. Failure to produce parts on schedule could lead to production delays, and the risk of having a machine out of service for an extended period is unacceptable to BAE System's pipe shop.

Remote troubleshooting

The managers making the decision were happy about the proximity of Unison's headquarters in the UK, which enables an engineer to make a service call within hours of a problem emerging. Another useful aspect of the machine is its incorporation of sophisticated software-based facilities that can be used for fault diagnosis. These include a camera that can be used to capture images or video of any operational problems. In combination with a software 'black box' that automatically stores the last 500 instructions entered by the operator, along with details of machinery positions from the servo motor sensors, Unison has detailed information to provide remote maintenance advice.

The Astute program is arguably the most demanding engineering project currently under way in the UK, and the nuclear-powered attack submarine has been described as 'more complex than the space shuttle,' involving nuclear weapons and stealth technology operating in the most hazardous environment on the planet. An Astute class submarine has around one million individual components and 10,000 separate design and engineering requirements.

Kevin Johnston, Integrated Work Team Manager at BAE Systems Submarine Solutions, comments: "We are driven by a demanding production schedule. The versatility of an all-electric tube bender, and one capable of making both right- and left-handed bends, is a major asset for my department, which will help us to keep major shipbuilding projects such as Astute running smoothly."

Alan Pickering of Unison adds: "Naval shipbuilding is possibly the most demanding application there is for tube bending machinery. A constant stream of application-specific parts are required, and they typically need to be produced just-in-time as work progresses along the vessel. The software-centric nature of all-electric tube bending machines - with their attributes of fast and accurate set-up, and ultra-precise bending - provides versatile automation to support this highly dynamic work environment."

To save space, the new tube bender incorporates on-machine guard panels. This feature will simplify moving the machine if required, for any reorganisation of the shipyard required for subsequent construction projects such as the UK's Future Aircraft Carriers.

For more information about Unison's all-electric CNC tube benders, go to

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