Lehrstuhl für Fertigungstechnologie, Universität Erlangen-Nürnberg

Supervision and Control during Laser Material Processing

Datum: 28.07.2003


  • Prof. Dr.-Ing. Dipl.-Phys. Andreas Otto


  • Prof. Dr.-Ing. Dr.-Ing. E.h. mult. Dr.h.c. M. Geiger
  • Prof. Dr.-Ing. Dr.-Ing. E.h. mult K. Tönshoff, Universität Hannover

The University of Erlangen-Nuremberg has conferred the qualification as a university lecturer on Dr. Otto. The final step to obtain this qualification was a public lecture on "Laserassisted Adjustment of Microparts", which was hold by Dr. Otto on July 28th. Before this he presented a recapitulatory publication on his works on "Supervision and Control during Laser Material Processing".

Due to the constantly rising requirements towards products to be manufactured and because of the increasing automation and robustness of the manufacturing processes systems for quality supervision and control gain more and more in importance. With their continuous improvement laser manufacturing processes, although they are already quite popular, will expand even further. Such quality control systems can be divided into two main categories: quality-supervising and preventively working systems. The recapitulatory representation gives an overview of the quality assurance systems presently available or still in research and/or under development, whereby the thesis focuses on monitoring, controlling and regulation of the laser beam welding process. From technical and economic point of view the quality assurance for this process is particularly interesting, since joining processes are often situated at the end of the process chain, which results in a high creation of value. In addition, laser beam welding opens up new possibilities for the joining of safety-relevant construction units, for example also in the automobile and aeronautic industry. In these branches a zero-error production must be ensured. As a rule is the quality of the joints even today only guaranteed by time consuming optical examination of all welding seams. This demonstrates the obvious demand for automated supervision and control systems for laser beam welding. The process of laser beam welding is also very interesting from the scientific point of view, since it exhibits strongly nonlinear dynamics caused by the coupling of several highly dynamic subsystems (melting bath, keyhole, metal steam/plasma, beam generation, etc...). This means that for the analysis, control and regulation of the process methods based on chaos or system theory have to be developed and used. The presented concepts show that these methods of signal processing and process control lead to a significant improvement in the quality of manufacturing and simultaneously increase also the robustness of the processes.