Modellgestützte Determinierung der Strahlcharakteristika beim Elektronenstrahlschweißen und ihre Auswirkung auf das Prozessresultat
| Autor: | Ufer, Sebastian |
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| Jazyk: | němčina |
| Rok vydání: | 2022 |
| Předmět: | |
| DOI: | 10.18154/rwth-2022-10651 |
| Popis: | Dissertation, RWTH Aachen University, 2022; Düren : Shaker Verlag, Aachener Berichte Fügetechnik 4, 1 Online-Ressource : Illustrationen, Diagramme (2022). = Dissertation, RWTH Aachen University, 2022 Due to the vacuum processing and the electrical control of all process-defining parameters, the electron beam welding process is a joining process with comprehensively defined process boundary conditions. Nevertheless, the testing of α and β samples before and after series production are also mandatory for qualified processes. The reason for this is the regular intervention in the beam generator assembly when changing the cathode. In particular, welding processes in the physical limit area have problems of the welding direction-dependent weld seam shape, which can be traced back to the cathode. Reliable information about the power density distribution in the beam is often missing at this point, which is why the process result is used as the quality measurement variable. The possibilities of beam measurement appear here as an alternative to ensure process quality without the expense of destroying components. Although specific beam measurement systems from machine manufacturers have recently spread, it is not foreseeable that the operator and quality assurance will rely solely on the results of the beam measurement. The reasons for this are based in the thematic complexity of the beam measurement. There is a lack of a generally applicable standard for carrying out and evaluating measurements while at the same time comparing the results of the various measurement principles. In addition, there is no interpretation basis for evaluating the measurement result with regard to its influence on the welding result. In order to approach the problem outlined above, a beam measurement system is first developed and optimized in operation. The analytical consideration leads to the elimination of numerous error influences on the measurement results, so that these ultimately prove to be reliable. In the next step, the measuring device is used for the metrological determination of the influence of defined errors in the beam generator. At the same time, the effect of these errors on the process result is determined on the basis of welding tests. In order to explain the influence of the geometric conditions in the triode on the power density distribution in the beam, the electron beam propagation is finally calculated as an example. Instead of the widespread models, no normally distributed emission is assumed, but one that comes close to the real geometry. The results of beam measurements, welding tests and analytical considerations as well as the cross comparison prove to be substantially conclusive. Published by Shaker Verlag, Düren |
| Databáze: | OpenAIRE |
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