System Development

The potential of dynamic beam oscillation for the laser cutting process lies in the improvement of the cutting edge quality or the increase of the cutting speed at the same laser power. The inclusion of two- and increasingly three-dimensional oscillating beam motion in the variable parameter field of laser cutting opens up opportunities for process optimization and raises new questions. The development progress is strongly influenced by system-technical possibilities or defines the requirements for the system technology. Many years of experience in the development of application-adapted processes, a strong partner network and the know-how in the development of our own system and control technology pilot solutions contribute to the constant gain in knowledge and the successful implementation of projects.

Sensor technology provides the data basis for optimizing a cutting process in terms of speed and quality and for stabilizing it for use around the clock. For thermal processes, the temporally and spatially resolved temperature field of the process zone provides immense information about the current state. By combining competences in camera technology, temperature calibration, optical design and process know-how, a sensor system has been developed which enables temperature field detection and evaluation under the specifics of a cutting process, a nozzle as aperture diaphragm and constantly changing observation planes. This is possible both for the standard process and in combination with dynamic beam shaping. 

Current work deals with the use of AI algorithms to make the developed hardware solution usable for process control.

In addition to melting, the expulsion of the molten material is an essential part of the process, which significantly influences the cutting speed and quality.  In cooperation with the process design and analysis group, simulation and experiment are combined and new findings are developed for increasing performance, improving cutting edge quality and reducing gas consumption.

In mechanical processes, tool wear and the introduction of force into the workpiece are the drivers for the search for alternatives for cutting hard or soft materials. Laser cutting offers itself as a suitable technology here due to the always sharp and non-contacting tool. The process defines its cutting power via absorption behavior, specific melting temperature and thermal conductivity of the material to be cut. Due to the scalability of the laser power, the movement dynamics of the laser system currently limit the achievable process speed. In the case of laser longitudinal cutting, the motion dynamics are no longer a limiting element.

An experimental setup developed at Fraunhofer IWS now sets almost no limits to the feed rate and thus enables investigations on laser longitudinal cutting at extreme feed rates. The laser source, optics configuration as well as the material to be cut can be flexibly selected. In addition, high-speed images of the cutting process can be recorded to support individual process design. Within the scope of process studies, Fraunhofer IWS cut grain-oriented electrical steel sheets of 230 micrometers thickness at a speed of up to 500 meters per minute in series quality. They succeeded in shifting the previously existing limits in such a way that now the melt expulsion capacity is considered the new limiting element. The findings on melt expulsion obtained from high-speed recordings generate important insights into requirements for improved nozzle design, which are essential for the design of a process suitable for series production. The experimental environment is suitable for subjecting longitudinal laser cutting systems for a wide range of materials to a "proof of concept" without the need for costly setup.