System for the investigation on the material processing using a blue emitting laser source

• Subject Area: Production Technology
• Term: Funded in 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 552212495

The processing system applied for as part of this large-device initiative consists of a diode laser that emits in the blue wavelength range, a high-speed camera (HS camera), and a high-precision axis system. The aim of the project is to develop a fundamental understanding of the interactions in material processing with blue laser radiation. This is particularly important in view of the cost potential of (blue) diode lasers compared to (green) disc lasers. The HS camera is used to analyse the specific process characteristics (e.g. melt pool dynamics, formation of the vapour flare, spatter formation) with high temporal and spatial resolution depending on the applied process strategy. The axis system in turn is used to precisely position and move the workpiece and align it in relation to the processing optics and the HS camera. This allows the region of interest, the range of which varies depending on the laser-material-process to be analysed (e.g. hardening, welding, cutting, additive manufacturing), to be adjusted by laterally aligning the HS camera in relation to the laser beam. Due to the increased absorption of metallic materials with short-wave laser radiation, it is important to understand the relationships between energy coupling and the resulting process outcome. This comparison is carried out using different laser beam sources with different wavelengths. Another significant influencing factor in material processing with blue laser radiation is the poorer focussability compared to infrared and green beam sources with significantly higher beam quality. For this reason, the potential of the proposed laser beam source for a wide range of laser material processing applications is to be analysed against the background of beam quality. For example, critical threshold values for the occurrence of different process and defect mechanisms (e.g. in heat conduction welding or deep penetration welding) are to be identified and correlated with various parameters (including beam diameter, intensity distribution, dimensions of the weld seam). Based on this, an understanding on the potential of beam shaping with blue laser radiation is to be developed. By locally modifying the energy input into the workpiece, the limitations of a reduced output beam quality are to be counteracted. Various approaches for modifying the input beam (diffractive optical elements, deformable mirrors) and their influence on the process quality in laser material processing (e.g. in laser beam deep penetration welding) are being analysed. The aim is to enable resource-efficient material processing by establishing beam shaping approaches for blue laser radiation and at the same time to shift the process limits that have already been identified.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Bearbeitungssystem zur Untersuchung der Materialbearbeitung mit einem blau emittierenden Lasersystem
• Instrumentation Group: 5700 Festkörper-Laser
• Applicant Institution: Friedrich-Alexander-Universität Erlangen-Nürnberg
• Leader: Professor Dr.-Ing. Michael Schmidt