Drilling millions of holes one after the other takes time, but can be done faster with the multibeam process, in which a matrix of identical beams is generated from a laser beam via a special optical system. Fraunhofer ILT used this process with an ultrashort-pulse laser (TruMicro 5280 Femto Edition) to drill holes simultaneously with 144 beams. The basis for such applications is detailed process knowledge, which has been collected at Fraunhofer ILT over decades and implemented in corresponding models and software. Thanks to this expertise, parameters can be varied on the computer and optimum process parameters found quickly. The robustness of the process can also be analyzed before the application is tested.
In parallel to this drilling application, a consortium of six partners is working on how to best integrate a multi-beam processing system into an industrial machine. In the EU project Multiflex, researchers along with the industry are increasing the productivity of scanner-based laser material processing using multi-beam processes. The special feature of this project is that all partial beams can be individually controlled and, thus, used to produce any kind of surface structure. The project partners aim to increase the speed of the process by a factor of twenty to fifty, thus making the entire process significantly more cost-effective.
Process knowledge is also a critical factor in further scaling up materials processing with ultrashort laser pulses with or without multibeam optics. When power is increased into the kilowatt range, thermal damage to the workpiece can occur. Such effects are explored through complex simulations, and processes can be adapted accordingly.
The laser systems for such experiments are available in the application laboratory at Fraunhofer ILT in Aachen. They are part of the Fraunhofer Cluster of Excellence Advanced Photon Sources CAPS, where 13 Fraunhofer institutes jointly develop laser beam sources, process technology and applications for USP laser powers up to 20 kW. A second CAPS laboratory is operated at Fraunhofer IOF in Jena.