The Laser Zentrum Hannover e.V. (LZH) and three industrial partners have set a goal to achieve up to 400 percent higher process speeds for deposition welding of wear and corrosion protection layers on large work pieces. An absolutely new process combination of a non-transmitted light arc and laser-based warming of the work piece will be developed within the project HoDopp, which is for small and medium sized enterprises.
The welded material has a very high purity level, and should provide work piece protection with the very first layer applied.
In the gas metal-arc welding process currently in use, a light arc melts the wire electrode and the work piece simultaneously. The mixing rate for the materials is 30%, meaning that the coating process must be repeated up to three times to ensure sufficient quality of the protective layer. Using this process, with maximum deposition speeds of 5 kg/h, it can take up to 24 hours to coat a square meter area, and energy and personnel costs are high.
This can be achieved by combining two separate processes in a completely new way. In the southern German company MERKLE, a modified gas metal-arc deposition welding process is currently being optimized, in which the light arc burns between two electrodes, but does not come into contact with the work piece. By adapting the nozzle form and the burner position, and by reducing amount of the protective gas, a stable and sputter-free process is possible.
A second process step is being developed in the Materials and Processes Department at the LZH. A diode laser of the newest generation with a low output level of under 0.5 kW is used to achieve a low but homogeneous penetration depth on the work piece. The laser focusses on and melts work piece shortly before the melted wire meets the surface. A deflector device is used to the control temperature distribution.
For Jörg Hermsdorf, Head of the Machines and Controls group, this combination of the individual processes is ideal. “This combination can be used to exploit the advantages of both tools. High energy input is needed to melt the deposition material, and this is provided by the light arc. On the other hand, the laser uses a low output power and can be used for precise, guided control of joining the melted material to the base material.“
By combining this innovative light arc process with inexpensive diode laser technology, the project partners have calculated that process time can be reduced to only 6 hrs. for one square meter, making deposition welding highly attractive for areas larger than 1 x 2 meters. Being inexpensive and faster and at the same time with higher quality, this innovative process is interesting for many applications. Apart from the conventional tool and mold making applications in the automotive industry, this process can also be used for protective layers on shafts, rollers and clamping devices, for repairs on damaged transport systems, or for protective layers on the stressed areas of oil drilling shafts.The project HoDopp is financed by the German Federal Ministry of Education and Research (BMBF) within a program for SME innovative production researching. Apart from the LZH and MERKLE, the firms G+F Strate GmbH and Druckguss Service Deutschland GmbH are taking part in the project, and are responsible for testing and quality assurance.
Michael Botts | Laser Zentrum Hannover e.V.
New manufacturing process for SiC power devices opens market to more competition
14.09.2017 | North Carolina State University
Quick, Precise, but not Cold
17.05.2017 | Fraunhofer-Institut für Lasertechnik ILT
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
22.09.2017 | Life Sciences
22.09.2017 | Medical Engineering
22.09.2017 | Physics and Astronomy