A matter of form

An old technique from the shipyards could be making a hi-tech comeback in aerospace. Laser forming, based around the same principles as the venerable technique of flame bending, could be used to ensure that complex assemblies of welded parts all fit together easily, according to engineers at

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Flame bending, explained lead researcher Andrew Moore, has been used by engineers since the 19th century. It works by creating stresses within a single piece of metal by careful application of heat. ‘If you heat up a small area of metal rapidly, you’ll make the hot area expand, and that yields against the cooler material and the whole piece bends,’ he said. ‘The key to it is forcing the rapid expansion in a confined space, and the temperature gradient that sets up the stresses.’

The Heriot-Watt team, in the Applied Optics and Photonics Group under Prof Duncan Hand, is bringing the technique up to date. In place of the flame are high-powered lasers, with their ability to apply intense and closely-defined heat to small areas. The goals are also different, said Moore. Rather than bending a piece of metal into the specific shape needed for a project, the team is looking at correcting bends imparted by welding so that assemblies regain their specified shape.