The simulation of laser-based production processes has to cover a wide span of time and length scales, especially in new techniques from micro- and nanophotonics. This requires special algorithms which have already been used successfully at the Fraunhofer Institute for Laser Technology ILT, as well as a massive amount of computer power. Fraunhofer ILT has built a high-performance computer cluster at the "Center for Nanophotonics".
In laser-based production operations, important process variables are difficult to measure in the micrometer-scale process zones owing to the tiny dimensions and very high temperatures that prevail. Computer simulations are therefore being increasingly used to optimize performance. They provide an insight into the processes and are easier to automate and often more cost-effective than experiments. What’s more, simulations enable fluctuations and measurement uncertainties to be excluded or specifically taken into account.
Multiscales – no problem for the computer cluster
Simulations of laser-based production processes tend to be multi-scale problems, in which a large expansion of the component has to be calculated at a very high resolution. Micro processing requires a resolution of a few nanometers and a calculation area with an expansion of several millimeters. For example, when processing thin-film solar cells, structures must be ablated extremely precisely and evenly from the layers which are just a few 100 nanometers thick.
Nano for macro
But in macro processing too, e.g. steel plate cutting, it is becoming increasingly important to be able to control small-scale effects in order to expand the process limits. To optimize expulsion of the molten metal during laser cutting, for instance, boundary layer phenomena of ultrasonic gas flows in the kerf are analyzed in detail.
(NanoTechWire)
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