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.