Dynamic beam modulation for optimization of industrial laser processes (FastShape)

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7Two difficult processes of laser material processing with efficient solid-state lasers (at a wavelength of approx. 1 µm) are the focus of this project: On the one hand, the fusion cutting of steel sheets with thicknesses of 8-20 mm with good quality with efficient solid-state lasers has long been a wish of many industrial users. On the other hand, the switch to electromobility requires high-quality and efficient joining processes for electro-copper sheets with thicknesses in the 0.5-3 mm range. Both laser cutting of thick steel sheets and laser welding of copper with solid-state lasers still show process instabilities, which lead to massive deficits in quality and performance, thus hindering a broad industrial implementation of these applications.Fundamental investigations at IFSW have already shown that these instabilities can be suppressed by influencing the geometry of the interaction zone (IA-zone) of the laser with the material and that an optimization of the processing results can be achieved. This was verified experimentally with the X-ray system of IFSW, which is unique in Europe. Using X-ray technology and IFSW's own polarization goniometer, the geometry of the IA-zone can be recorded and displayed during machining.Empirical studies at the IWS have shown that a significantly improved quality and performance can be achieved for cutting and welding processes by using dynamic beam modulation. Dynamic beam modulation in the system engineering sense used here includes in particular the fast temporal and spatial deflection of a laser beam with respect to its static propagation axis moved in relation to the processed material according to the processing speed and, if required, a position-dependent high-frequency power control.In the planned research project, the physical mechanisms of action of the dynamic beam modulation on the geometry of the IA-zone and the resulting process result are to be identified in order to adapt and optimize the methods of dynamic beam modulation used at the IWS to the exemplary applications of the cooperation partners with the aid of the diagnostic techniques developed at the IFSW for implementation. The aim is to be able to adjust the geometry of the IA-zone actively and reproducibly for the given applications and thus to be able to demonstrate an increased quality and performance of the specified exemplary applications of cutting and welding.