Lehrstuhl für Fertigungstechnologie, Universität Erlangen-Nürnberg

Laser Forming of Extrusions



Datum: 29.09.1997


Author


Reporter

  • Prof. Dr.-Ing. Dr. h.c. M. Geiger
  • Prof. Dr.-Ing. K. Roll, Stuttgart

The aim of this project was the development of a flexible rapid prototyping process for bending extrusions. The forming is carried out by means of laser induced thermal stresses, i.e. no external mechanical forces are necessary and therefore it is a kinematic bending process. To realize this aim, first of all basic process knowledge had to be investigated. Therefore the Finite Element Method was used and the results were verified experimentally as far as possible. The knowledge gained by this strategy was employed to build up an analytical process model. Herewith it is possible to estimate the resulting deformations and the number of irradiations necessary to achieve a desired curvature. The bend angle for a single irradiation is typically between 0.1° and 0.5°degrees. The total bend angle and the radii are determined by the number of irradiations and the gap between the irradiations in extrusions’ axis direction. The basic process knowledge is stored computer assisted in form of a technology processor. The technology processor analyses the workpiece shape in the CAD-model and generates automatically the NC-programs under consideration of material, machine- and process-parameters. For the machining a CO2 laser with 2.2 kW laser power was used, a 5-axes-gantry robot with an additional rotary axis was employed as guiding system.