All-electric tube bender cuts scrap and energy costs on nuclear submarine construction

The Astute programme involves the production of a large number of complex tubular parts, often in small quantities and made from expensive alloys, such as corrosion-resistant cupronickel, on a just in time basis as work progresses along the vessel. Image: Unison technology helped construct this Image: Under build The Unison tube bending machine, featuring precision software-controlled servomotor movement, will be able to bend tube diameters up to 76 mm. Its advanced laser measurement system will monitor any deviations from the programmed bend caused by the tubing material's spring back characteristics and make adjustments automatically to produce the correct shapes. The elimination of scrap provided by Unison's spring back correction system, which is believed to be unique on the tube bending market, was an important factor in BAE's buying decision. This technology is already in use at the company's sister site in Scotstoun, UK, where BAE Systems Surface Ships is employing a laser-measurement-equipped Unison bender on the construction of the Royal Navy's Queen Elizabeth class aircraft carriers. The need for the new machine arose as a result of a decision to replace an ageing hydraulically-powered tube bender. As the all-electric Unison machine has no need to run a hydraulic pump continuously, power is only required when the machine is actually forming a bend, so energy consumption is reduced substantially, typically by around 90%. Unison has been required to design the machine so that it will be able to accept all of the existing tooling used by the old 60 mm hydraulic machine, and develop a software link to BAE Systems' central database, where the construction information is stored. This utility automatically creates a bending program from the part specification, allowing the business to set up the bender for a new part in seconds, if the tooling is already on the machine. "All-electric benders are ideally suited to the naval boat building environment, as their software-controlled set-up provides versatile support for the constantly changing workload," says Jim Saynor of Unison. "With material costs spiralling, we have seen an upsurge in demand for our spring back correction system as well, and this feature should eliminate virtually all of the scrap that can be commonly generated when manually setting up a hydraulic machine for a precision bend." The seven-boat Astute programme is described one of the largest and most complex engineering projects under way in the UK today. An Astute class submarine has a million individual components and 10,000 separate design and engineering requirements. The first-of-class HMS Astute has been handed over to the Royal Navy and is completing sea trials before going into operational service. Second-of-class Ambush is undergoing final commissioning and testing at Barrow before leaving for sea trials. Boats 3, 4 and 5 are in various stages of build and steel is due to be cut on the sixth submarine in 2012. First published online