Browsing by Author "Feuer, R."

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    High-quality percussion drilling with ultrashort laser pulses
    (2021) Feuer, Anne; Weber, Rudolf; Feuer, R.; Brinkmeier, David; Graf, Thomas
    The influence of the laser fluence on the quality of percussion-drilled holes was investigated both experimentally and by an analytical model. The study reveals that the edge quality of the drilled microholes depends on the laser fluence reaching the rear exit of the hole and changes with the number of pulses applied after breakthrough. The minimum fluence that must reach the hole’s exit in order to obtain high-quality microholes in stainless steel was experimentally found to be 2.8 times the ablation threshold.
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    ItemOpen Access
    Investigations into the occurrence of microstructures by means of in-situ depth measurements during percussion drilling with ultrashort laser pulses
    (2025) Feuer, Anne; Feuer, R.; Boley, Steffen; Förster, Daniel J.; Neuenschwander, Beat; Hagenlocher, C.; Michalowski, Andreas; Graf, Thomas
    A model-based data analysis of the depth measurements performed during percussion drilling in stainless steel reveals the occurrence of microstructures by observed deviations from model expectations. For the data analysis, an adaptive correction factor cAwas introduced into an analytical drilling model to account for changes in the absorptance caused by the microstructures. The analysis of the temporal evolution of cAduring drilling shows that the presence of microstructures coincides with an increased absorption, while the formation of a single borehole tip is associated with a reduced absorption.