Postdoctoral lecture qualification

Title Knowledge based procedures for the process design of manufacturing processes

Reporter

Prof. Dr.-Ing. Dr.-Ing. E.h. mult. Dr. h.c. mult. Manfred Geiger
Prof. Dr. Frank Vollertsen, Universität Bremen
Prof. Dr.-Ing. Klaus Meyer-Wegener

Report
Dr. Hagenah achieved his postdoctoral lecture qualification after all reviews had arrived and the Faculty Council had accepted them at the end of the display period at Feb. 26 th 2010. He published the results of his work in a book entitled “Knowledge Based Methods in the Design of Manufacturing Processes”. Within the book different methods for the acquisition, the archiving and the application of knowledge in the field of manufacturing process design are introduced and explained using different examples from production.

About the topic of the book:
Knowledge handling is gaining importance as a competitive factor. The step of knowledge acquisition including the needed abstraction from experimental work into models is of the same importance as the transparent methods for knowledge archiving and application. In his postdoctoral lecture thesis Dr. Hagenah has introduced methods for each of these steps and illustrated their application in manufacturing industry by using different production processes as examples. The covered scope reaches from design of experiments through fuzzy logic and artificial neural networks to genetic algorithms. The width of the discussed subjects gives both a good insight and overlook of knowledge based methods.

Title Characterisation of Sheet Metals for Light Weight Constructions

Reporter

Prof. Dr.-Ing. Dr.-Ing. E.h. mult. Dr. h.c. mult. Manfred Geiger
Prof. Dr.-Ing. Friedrich-Wilhelm Bach, Leipniz Universität Hannover
Prof. Dr.-Ing. Hartmut Hoffmann, TU München

Report
July, 26th Mrs. Dr. Merklein finished her postdoctoral lecture qualification, giving a lecture entitled “Holistic interpretation and layout of manufacturing processes chains”. In addition a book about the characterisation of sheet metals for light weight constructions was published, in which the possibilities of determination of material input data and models for finite element simulation are described.

About the topic of the book:
Characterisation and modelling of materials forming behaviour are important aspects in the field of finite element simulation and the numerical process analysis. Caused by the technical developments of the last years and the development of new steel and aluminium grades a lack of knowledge about the forming behaviour has grown. Therefore it is important to enhance the possibilities to characterize materials formability in dependency of the stress and strain condition as well as temperature using modern technical solutions, as for example optical strain measurement systems. Especially for the determination of true stress – true strain curves and forming limit diagrams newest developments and trends are shown and explained. The meaning of material characteristics for the FE based process analysis is demonstrated using exemplary forming processes.

Title Supervision and Control during Laser Material Processing

Reporter

Prof. Dr.-Ing. Dr.-Ing. E.h. mult. Dr. h.c. mult. Manfred Geiger
Prof. Dr.-Ing. Dr.-Ing. E.h. mult. Hans Kurt Tönshoff, Leipniz Universität Hannover

Report
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".

About the topic of the book:
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.

Title Laser forming - laser assisted shaping: methods, mechanisms, modelling

Reporter

Prof. Dr.-Ing. Dr.-Ing. E.h. mult. Dr. h.c. mult. Manfred Geiger
Prof. Dr. rer. nat. Hael Mughrabi

Report
In the course of the qualification as a university lecturer Dr. Vollertsen has presented his monograpyh "Laserstrahlumformen - Lasergestützte Formgebung: Verfahren, Mechanismen, Modellierung" in May 1996. The procedure has been finished on 20.12.1996 with a public lecture.

About the topic of the book:
A new genearation of laser methdos develop since a couple of years. They will influence the production technology similar to the effect of the introduction of the laser beam as a tool. These generation is formed by the laser assisted shaping technologies, which are described and systematizised in this book. A special emphasis is set to laser forming as a method of rapid prototyping and aligning. The book offers an overview about the possibilities to realize or enhance shaping by cutting, joining, primary shaping or metal forming using a laser beam. These technologies can be systematizised in laser technologies, laser assisted technologies and laser integration. Besides applications to mass production the application in the field of rapid prototyping is demonstrated. In order to give a complete overview some well established methods are also integrated which do not use a laser beam. Laser forming is described in respect to the mechanisms, the models and the influences, both the influence of thw workpieces parameters on the process and the influence of the process on the workpiece. Som possible applications are shown, summarizing the stat of the art.

Title Load on and strength of tools in bulk metal forming

Reporter

Prof. Dr.-Ing. Dr.-Ing. E.h. mult. Dr. h.c. mult. Manfred Geiger
Prof. em. Dr.-Ing. Dr. h.c. Kurt Lange, Universität Stuttgart

Report
The University of Erlangen-Nuremberg has conferred the qualification of university lecturer on Dr. Engel. As final step of the procedure to obtain this qualification, Dr. Engel has presented on July 3rd a public lecture on "Microforming - umformtechnische Herstellung von Kleinstteilen". anoterh step before was the publication of his postdoctoral thesis on "Beanspruchung und Beanspruchbarkeit von Werkzeugen der Massivumformung"

About the topic of the book:
The qualitiy of too, which can be characterized by its service life, its reliability and its precisisch, represents a decisive criterion for economical and safe processing in bulk metal forming. Thus it is an imperative demand fo an optimump process to make this criterion available already in the phase of laying out the process. In this monograph the stat of the art on such methods of assessment is compiled. Starting from this basis, a concept fo the prediction of tool life and tool reliability is derived, which can be applied quite efficiently in planning, laying out and optimizing the forming process. The kernel of this concept is a formulation well known from the general reliability theory in engineering: the systematic, deterministic-probabilistic analysis of load on and strenght of the tool. The deterministic component of the concept is given by the numerical process simulatin in combination with the modelling of the specific failure mechanisms on the basis of tribological methods and methods of damage mechanics as well as fracture mechanics. The stochastic phenomena can be quantified by statistical formulations. The combination of both the deterministic and probabilistic component, which can be realized by the interference analysis, yields an universal planning instrument - a kind of extentded process simulation -, which enables not only an estimate of tool life and tool reliability, but also an identification and an assessment of those primary parameters of influence, which most significantly affect the tool performance. Capabilities and future applications of this concept are shown by examples considering the optimization of forming processes.