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%0 Thesis %A Brosda, Maximilian %T Erhöhung der Selektivität und Präzision beim Schweißen von mehrschichtigen Thermoplastfolien durch den Einsatz von wellenlängenangepasster Laserbearbeitung; 1. Auflage %I RWTH Aachen University %V Dissertation %C Aachen %M RWTH-2024-08127 %@ 978-3-98555-229-0 %B Ergebnisse aus der Lasertechnik %P 1 Online-Ressource : Illustrationen %D 2024 %Z Druckausgabe: 2024. - Auch veröffentlicht auf dem Publikationsserver der RWTH Aachen University. - Weitere Reihe: Edition Wissenschaft Apprimus %Z Dissertation, RWTH Aachen University, 2024 %X Polymer films are used in many areas of industry. Polymer films are an outstanding option, especially where flexible and cost-effective implementations are required. The spectrum of applications for polymer films ranges from packaging technology, medical technology and the automotive sector to high-end applications in the field of OLED/OPV encapsulation. Polymer films are mostly developed for the individual application in order to obtain the greatest possible intersection for the defined given property requirements. A significant proportion of the polymer films used are transparent to the human eye. In addition to aesthetic and sales promotion aspects, this also has safety-related reasons. In the encapsulation of flexible OLEDs or OPVS, transparency is mandatory due to technical constraints. Usually, the previously specially developed films are produced in rolls by specialized manu- facturers and then only further processed independently at the user or goods producer. The central step in a further processing operation is joining. In joining, a polymer film is welded to itself or to another joining partner, for example to of a cup. Tools with a geo- metrically fixed shape, e.g., heat-sealing jaws or ultrasonic rollers, are established for this purpose. Increasingly, aspects of format flexibility, resource efficiency and quality are play- ing an important role in the selection of technologies for the further processing of polymer films. These are requirements for the number of products down to batch size one, minimi- zation of the variety of polymers used in a film composite to achieve better recyclability, and reproducible and quality-relevant verifiable joints to increase product safety. The tech- nological approaches available on the market to date can only offer limited solutions to these complex requirements. Therefore, this thesis investigates the extent to which diode and fiber laser systems with adapted emission wavelengths can provide answers to these requirements. For this purpose, energy deposition by means of laser radiation is considered based on the central step of joining using wavelength-matched laser beam sources. From this process variant, in turn, other processes such as laser-based cutting can be derived. To investigate the suitability of wavelength-matched laser beam sources for welding polymer films in more detail, aspects of the interaction of the irradiated laser radiation with the individual layers of a polymer film composite and the resulting heat conduction processes are physically described and investigated. The observation and demonstration are based on simulations of beam propagation and heat conduction in 3D space as well as on imaging thermographic recordings and thin sections of physical weld specimens. The application in production also requires statements about the influence of individual process parameters on the joining process. For this purpose, experimental investigations are carried out on commercially available and representative polymer foils. The requirements for quality assurance are considered with investigations into suitable infrared, thermographic, spectral and imaging sensors. In the future, a hybrid and simultaneous laser-based joining and separa- tion process for multilayer polymer films will be considered. %F PUB:(DE-HGF)11 ; PUB:(DE-HGF)3 %9 Dissertation / PhD ThesisBook %R 10.18154/RWTH-2024-08127 %U https://publications.rwth-aachen.de/record/992290