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.
High computer power in the »Center for Nanophotonics«
The required large number of grid points exceeds the capacity of conventional workstations in terms of processing time and storage space. The funding provided by the state of North Rhine-Westphalia for the new »Center for Nanophotonics« in Aachen has made it possible to create a high-performance computer cluster for simulations of these multi-scale tasks at Fraunhofer ILT. The final stage of the high-power computer system was installed and started up in November. In developing the concept, the research scientists in Aachen deployed a heterogeneous computer architecture consisting of multi-core processors and special high-performance computers with CUDA architecture, which allows parts of the calculations to be performed on graphics processors (GPUs). This modern concept is particularly suitable for the massively parallel execution of frequently recurring calculation steps. The installed cluster system has 376 CPUs and eight graphics processor systems with altogether 1920 GPUs. The storage capacity amounts to close on 2 terabytes of main memory and 67 terabytes of hard disk storage, of which 20 terabytes are on redundant interconnected drives. Data is exchanged within the cluster by means of a fast InfiniBand network. The theoretical total computer power is close on 10 teraflops, which roughly corresponds to the power of 1,000 modern office PCs. »The system is available to us around the clock on an exclusive basis. This means that simulations can be performed specifically for laser processes, to further our research and on behalf of customers, without any long waiting times. This makes our work much easier while also saving time and money,« explains Dr. Jens Schüttler, project manager at Fraunhofer ILT.
The new high-performance computer system can be used to simulate complex operations from laser material processing at high resolution in a short processing time. Applications include molecular dynamic simulation of ablation with ultra-short pulses, the configuration of micro processing techniques and the design of gas flows and gas-cutting nozzles. The propagation of laser radiation at wavelength scale and the stability of the melting dynamics in laser cutting can also be simulated. This range of applications is interesting for manufacturers and users of laser processing machines who want to analyze, optimize and improve their processes.
Axel Bauer | Fraunhofer ILT
NASA detects solar flare pulses at Sun and Earth
17.11.2017 | NASA/Goddard Space Flight Center
Pluto's hydrocarbon haze keeps dwarf planet colder than expected
16.11.2017 | University of California - Santa Cruz
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses