Laser assisted forming of sheet metals

Laser processes have proved to be very successful in many fields of production technology with the exception of forming, as for instance deep drawing or bending of sheet metals, although in the latter case bending around very small angles by inducing thermal tensions with a laser has found some applications. The latter lack of applications in forming is caused by the fact that plastic deformation asks for strong mechanical forces that cannot be generated with lasers. Nevertheless, the necessary forces can be strongly reduced by a selective laser heating of the workpiece in those regions, where the strongest deformations take place - in the case of bending around the bending edge - thus leading to softening of the material in these regions and facilitating deformation, finally reducing the necessary forces. The latter concept of laser assisted forming has been applied to bending and deep drawing of sheet metals with the main result that not only the forces necessary for the forming process are reduced, but that it is also possible to obtain forming without cracks and rupture even in the case of materials that are difficult to form at room temperature due to their brittle nature, as for instance Titanium. Moreover, experiments have shown that considerably stronger deformations can be obtained as in cold working. Compared to hot working, where the whole workpiece is heated, important technological advantages are obtained, as a reduction of processing time and a lack of surface degradation. In view of these advantages laser assisted forming could widen the limits of forming technology and also open new fields for beneficial laser applications.