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Although there have been numerous attempts to define how different laser polishing parameters affect the generated surface roughness, there has been no detailed investigation of how their effects can be combined to optimize the process. This paper applies statistical analysis to model and predict the resulting surface roughness for laser post-processing of components made of Ti-6Al-4V and produced by laser powder bed fusion. This model is based on analysis of a wide ranging experimental programme investigating how the interaction of the governing parameters, i.e., laser power, number of repetitions, axial feed rate, scanning speed, and focal position, affected surface roughness. The experimental programme was the result of a robust Design of Experiments analysis and experimental analysis using ANOVA. It is expected that the outcomes will contribute towards the understanding of how the governing parameters influence the laser polishing process and final surface roughness, and would be a tool for optimizing their selection. The results of the ANOVA (analysis of variance) revealed that the most significant parameters are scanning speed followed by laser power and then axial feed rate. In addition, a clear tendency for the estimated Ra to decrease with the increase in laser power at lower values of axial feed rate and of scanning speed, and a focal position in the region of 2 mm. It is noted that the process parameters were varied over wide ranges, including extreme values, which made it difficult to accurately model the dependent variable over the full range of experimental trials.

Der Beitrag gibt einen Überblick zu technologischen Möglichkeiten der hochpräzisen Laser-Mikrostrukturierung tribologisch beanspruchter Oberflächen. Die tribologische Wirkung von mit diesem Verfahren generierten mikroskaligen Oberflächenstrukturen werden erläutert. Dazu zählen die Reservoir-Wirkung, hydrodynamische Wirkung, Wirkung auf die Oberflächenspannung, Öl-Leitstrukturen und das Ableiten von abrasiven Partikeln. Neue Möglichkeiten ergeben sich durch die Kombination von mikrostrukturierten Oberflächen mit superharten Kohlenstoffschichten. Potentiale werden anhand von Anwendungsbeispielen präsentiert.

The main goal is to develop an optimized three-dimensional (3D) cell design with improved electrochemical properties, which can be correlated to a characteristic lithium distribution along 3D micro-structures at different State-of-Health (SoH). 3D elemental mapping was applied for characterizing the whole electrode as function of SoH. It was demonstrated that fs-laser generated 3D architectures improves the battery performance regarding battery power and lifetime. It was quantitatively shown by laser-induced breakdown spectroscopy that 3D architectures act as attractor for lithium-ions. Furthermore, lateral intrinsic porosity variations were identified to be possible starting points for lithium plating and subsequent cell degradation. Results achieved from post-mortem studies of cells with laser structured electrodes (intrinsic and artificial porosity variation), and unstructured lithium-nickel-manganese-cobalt-oxide electrodes will be presented.

Strukturen mit Mikrometerauflösung auf Außenflächen von Flugzeugen sollen sicherstellen, dass die Luftströmung glatt bleibt und der Luftwiderstand des Flugzeugs gering gehalten werden kann. Dafür haben Ingenieure am Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS, an der Technischen Universität Dresden und bei Airbus ein Laserverfahren erfolgreich angewendet. Diese funktionalen Mikrostrukturen können großflächig aufgebracht werden und die Wahrscheinlichkeit von Oberflächenkontamination durch Wasser, Insekten und Schmutz reduzieren.