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%0 Thesis
%A Lanfermann, Andrea
%T Verfahrens- und werkstoffspezifische Einflussfaktoren beim Laserpolieren additiv gefertigter Kunststoffbauteile
%I Rheinisch-Westfälische Technische Hochschule Aachen
%V Dissertation
%C Aachen
%M RWTH-2024-05760
%P 1 Online-Ressource : Illustrationen
%D 2024
%Z Veröffentlicht auf dem Publikationsserver der RWTH Aachen University
%Z Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2024
%X Components made of plastic are produced all over the world and the demand for them is continuously increasing. Indeed, plastic components in the most varied forms and sizes have become indispensable in many industries; what most components share, however, is the need for a functional surface. For example, optical lenses must have smooth surfaces to operate effectively, while automobile dashboards need rough ones to meet visual design requirements. Many conventional methods for producing a defined surface roughness are complex, costly or do not meet all the required quality standards. An alternative to them is laser polishing, which is already used for metals and glass with great success. Nonetheless, the process is not yet fully developed for plastics, and this is precisely where a lot of potential lies. In particular, the surfaces of 3D-printed plastic components are rough and often require surface smoothing for the intended applications. More comprehensive studies need to be conducted to work out the essential core parameters in order to better understand the laser polishing process. This dissertation presents investigations on the systematic relations between various process parameters as well as the correlation between temperature gradient, viscosity, surface tension and roughness reduction during laser polishing. A variance analysis showed that the temperature has the greatest influence on the laser polishing process. This is immediately followed by the scanning velocity and then the laser beam diameter. All process parameters considered significant have a large effect on the formation of the melt pool and, thus, on the flowability of the plastic melt. This leads to the hypothesis that the roughness reduction is systemically dependent on the viscosity of the material. This hypothesis was confirmed in the experiments presented here. For viscosities below η* = 500 Pa*s, roughness reduction increased exponentially with increasing viscosity, whereas above this limit it decreased almost linearly. The exponential increase below this limit suggests that at this point the relation between surface tension and viscosity is not suitable for smoothing the surface. This leads to the existence of an optimal temperature range where both forces fit together perfectly.
%F PUB:(DE-HGF)11
%9 Dissertation / PhD Thesis
%R 10.18154/RWTH-2024-05760
%U https://publications.rwth-aachen.de/record/987603