A systematic experimental investigation of fiber laser cutting stainless steel in a wide range of material thicknesses is performed. The achievable maximum cutting speed, the resultant thermal efficiency of the process as well as the surface roughness of the cut edges were determined using different optical setups and beam geometries. In order to find out some reasons for characteristic features of the fiber laser cutting process also the cut kerf geometries were analyzed. The systematic investigation clarifies the most promising procedural possibilities for improvements of cutting performance and cut edge quality in fiber laser cutting of stainless steel.

Sheet metals with thicknesses >8 mm have a distinct cutting performance. The free choice of the optical configuration composed of fiber diameter, collimation, and focal length offers many opportunities to influence the static beam geometry. Previous analysis points out the limitations of this method in the thick section area. Within the present study, an experimental investigation of fiber laser fusion cutting of 12 mm stainless steel was performed by means of dynamical beam oscillation. Two standard optical setups are combined with a highly dynamic galvano-driven scanner that achieves frequencies up to 4 kHz. Dependencies of the scanner parameter, the optical circumstances, and the conventional cutting parameters are discussed. The aim is to characterize the capabilities and challenges of the dynamic beam shaping in comparison to the state-of-the-art static beam shaping. Thus, the trials are evaluated by quality criteria of the cut edge as surface roughness and burr height, the feed rate, and the cut kerf geometry. The investigation emphasizes promising procedural possibilities for improvements of the cutting performance in the case of fiber laser fusion cutting of thick stainless steel by means of the application of a highly dynamic scanner

An increase of the cut quality or enhanced process efficiency is still an aim for cutting of thick metal plates with 1.07 μm laser radiation. Nowadays, linear polarization is well investigated for CO2-lasers as an approach to a solution. The same attempt is not explored as much for laser beamfusion cutting of thick metal plates with high power solid state lasers. For this case, the present letter examines the linear polarization in contrast to statistically polarized cuts

Best edge quality for thick metal plates is one of the current main challenges to create a unique selling proposition for laser cutting machines. Various approaches have been used to optimize the cutting performance of different materials. The reported results show in general that when a new material batch is loaded to the laser cutting machine, even of the same material type, diverse results are obtained. These differences have been attributed to fluctuations in the chemical composition of the used alloys. This letter analyses the influence of five different material compositions of Cr/Ni-steel (X5CrNi18-10/1.4301/SUS304/stainless steel) and compares achievable qualities and process windows using a solid state fusion cutting system. A larger process window is observed by increasing sulfur content of the material in this study.

The latest research on applying beam oscillation in laser beam fusion cutting revealed significant process improvements regarding speed and quality. The reason for this increasing process efficiency remains unexplained; however, theoretical investigations suggest the change in energy deposition (respectively heat conduction) as the cause. The present paper aims to analyze the energy deposition by a novel temperature measurement method. For this purpose, a conventional laser beam cutting setup was equipped with beam oscillation technology and a high-speed temperature measurement setup. Various characteristics of the temperature distribution in the process zone (spatial and temporal resolved temperature profiles, maximum and average values, as well as melt pool size) were evaluated for different conditions of beam oscillation (amplitude, frequency, cutting speed). Additionally, the geometrical properties of the process zone, defining the absorptivity have been measured. The comparison with static beam shaping reveals strong temperature volatility, which is induced by the way of energy deposition and an improved absorptivity over a substantial part of the cut front, with the overall result of enhanced heat conduction. For the first time, changed mechanisms applying beam oscillation instead of static beam shaping have been experimentally identified. Based on these measurements, a previously developed explanatory model was not only confirmed but also extended.