THE LASER BENDING OF STEEL FOILS FOR MICROPARTS BY THE BUCKLING MECHANISM - A MODEL

Samples of plain carbon steel (C75, e.g. SAE1074) and high-alloyed steel (X5CrNi1810, e.g. AISI304) were bent by means of laser bending with a 60 W Nd:YAG laser. The temperature gradient along the sheet thickness was small, resulting in a mechanism of laser bending, the buckling mechanism, different from the known temperature gradient mechanism. By means of this mechanism it is possible to bend sheets towards and away from the laser beam. Bending angles up to 10 degrees can be reached in one step only. The extension of the laser bending process in this manner makes it possible to use it in a wider field, especially for straightening operations. A process model shows that the mechanism active in the reported experiments can be described quantitatively by a buckling process. The bending direction can be controlled if all necessary information, concerning the sheet percurvature, internal stresses and so on, is known.