Laser cutting is based on various simultaneous sub-processes. Firstly, the focused laser beam provides the required energy to heat and melt the material. Secondly, the cutting gas flow accelerates the melt and removes the material out of the kerf. In addition, the melt flow and local phase transitions play an important role in the redistribution of energy within the process zone. The cut itself and the achievable process performance and quality are the result of the complex interaction of the sub-processes. Due to the momentum and heat transfer between the gas and the material, the gas flow has a decisive influence on cut quality and the formation of burr. Furthermore, the differences in quality for CO2 and solid-state laser cutting is linked to the influence of a changed gas flow due to wavelength dependent absorption effects.

This study experimentally evaluates dynamic beam shaping in beam propagation direction for cutting 20 mm thick stainless steel, with a focus on improving cut quality and reducing burr and surface roughness. Both 20 kW cw and 15 kW pw laser cutting tests were carried out for the first time. By using a novel tool to model the laser spot dynamics resulting from rapid focusing and defocusing, we achieved significant improvements in cutting performance. This tool also enabled the inclusion of cutting speed, nozzle geometry, cut contours and beam overlapping, providing a comprehensive understanding of the interaction between the laser beam and the workpiece. Our results demonstrate a reduction in burr formation and a decrease in the roughness of the cut edge, manifesting and highlighting the potential of dynamic beam shaping for enhanced laser cutting of thick stainless steel.

Burr formation in laser cutting reduces the quality of the cut and increases the need for extra processing of parts. In this paper in-situ high-speed imaging has been used to gain insights into the impact of the melt dynamics in the cutting kerf on the formation of burr during laser cutting of metal. The images captured both, the melt dynamics in the kerf and the adhesion of the melt to the lower edge of the sheet. The results show that the formation of burr is due to the detachment of melt droplets from the cutting front to the flanks of the cutting kerf, which then adhere to the rear side of the sheet. In addition, the adhesion of molten material at the rear side of the cutting front and the subsequent flow of the molten material along the lower edges of the cutting kerf also leads to formation of burr.

Latest research on laser cutting has revealed significant improvements in process productivity and cut quality through the applications of dynamic beam shaping techniques. The present work aims to study the effect of axial beam oscillations (along Z-axis) on laser fusion cutting process through analytical modelling and experimental investigations. While existing literature has primarily focused on dynamic beam shaping employing harmonic oscillations, this study explores the impact of various oscillation waveforms, including sinusoidal, triangular, square, ramp-up, and ramp-down patterns. Initially, an analytical model was developed to evaluate the laser power distribution within the process zone for different oscillation patterns. Furthermore, the effect of axial oscillations, superimposed on the cutting direction, was experimentally investigated using 20 mm thick AISI304 stainless steel. Experimental results demonstrate notable improvements in process performance through axial oscillation, either by reducing burr defects at the same processing speed or by increasing productivity while maintaining equivalent part quality.

Gigacasting facilitates the production of large, complex parts in a single process, reducing costs and increasing efficiency. After casting, laser cutting ensures a flexible postprocessing for precise contours, as well as removal of overflows and runners. High-Power Laser cutting of aluminum based gigacasted components with a thickness of up to 30 mm provides high quality production.

High-performance lasers, typically starting from 3 kW, are required for efficiently cutting thick aluminum. Maintaining a high working distance during the cutting process is essential, as it allows a three-dimensional accessibility of complex geometries. The laser beam melts the material, while assist gases like oxygen influences cutting quality.

This development of laser cutting for postprocessing gigacasting components enables lightweight, durable automotive components with complex geometries while reducing material waste. By combining these technologies, the production of future mobility parts is revolutionized, resulting in carbon reduction and better cost-efficiency for the product lifecycle.