Additive manufacturing processes are booming, with the rapid growth of the formnext trade fair a clear indication of this. At formnext 2018, the Fraunhofer Institute for Laser Technology ILT will be showing a new process in which the component in the powder bed is heated with laser diodes. As a result, distortion can be reduced, taller parts generated and new materials used.
In just three years, formnext has established itself as the industry meeting place to get the latest on additive manufacturing (AM) processes. With 470 exhibitors and nearly 22,000 visitors, the fair in Frankfurt is also an international leader.
Located in Aachen, the Fraunhofer Institute for Laser Technology ILT has been involved in formnext right from the start. Its scientists have developed a lot of expertise in the field of additive manufacturing processes.
They work on a wide variety of AM topics, from increasing efficiency to developing system concepts and processes or even qualifying new materials. In Frankfurt, several Fraunhofer ILT experts will be present in Hall 3.0 at Booth E70.
Heating with kW power from above
As a highlight, the team of Fraunhofer ILT will be presenting a new process this year. This process – laser powder bed fusion (LPBF), also known as laser beam melting – can build parts with less thermally induced stress and less distortion than conventional process technology.
The internal stresses are caused by temperature gradients in the generated component: In the laser spot, temperatures above the melting point prevail, while the rest of the component cools rapidly. Depending on the geometry and material, this temperature gradient can even lead to cracks in the material. To avoid this, the component is usually heated from below via the substrate plate. However, that's not enough, especially with taller structures.
As part of the Digital Photonic Production DPP research campus, a funding initiative of the German Federal Ministry of Education and Research (BMBF), the experts from Fraunhofer ILT are working together with their partner Philips Photonics to develop solutions for this task. In the joint project DPP Nano, they have developed a set-up in which the component is heated from above.
For this purpose, an array of six vertical-cavity surface-emitting laser bars (VCSEL) with 400 W each is installed in the process chamber. With infrared radiation at 808 nm, this array can heat the device from the top to several hundred degrees Celsius during the building process. The bars can be controlled individually so that sequences of different patterns are possible. The process is monitored with an infrared camera.
In a concrete experiment, the Aachen engineers have constructed parts of Inconel® 718 and demonstrated significantly reduced distortion. The component was heated up to 500 °C.
The VCSEL heating reduces the thermal gradient, thus also the stresses, making it possible to produce taller parts. But even more interesting are the possibilities that arise for particularly difficult materials; soon, components made of titanium aluminides are to be produced. For this, the component will be heated to approx. 900 °C.
Such parts are commonly used, for example, in the hot gas section of turbochargers. In addition to turbomachinery, the process also opens up new prospects for other industrial sectors where thermally induced stresses in additive manufacturing processes have to be reduced.
More information will be available at the joint Fraunhofer Booth E70 in Hall 3.0 from November 13 to 16, 2018 at formnext in Frankfurt am Main. In addition, Andreas Vogelpoth will present the topic “VCSEL-Based Preheating for LPBF” at the TCT conference @ formnext on November 15, 2018 at 3.00 pm.
Further information about the Digital Photonic Production DPP research campus:
Andreas Vogelpoth M.Sc.
Group Laser Powder Bed Fusion LPBF
Telephone +49 241 8906-365
Christian Tenbrock M.Sc. M.Sc.
Group Laser Powder Bed Fusion LPBF
Telephone +49 241 8906-8350
Petra Nolis M.A. | Fraunhofer-Institut für Lasertechnik ILT
Copper oxide photocathodes: laser experiment reveals location of efficiency loss
10.05.2019 | Helmholtz-Zentrum Berlin für Materialien und Energie
NIST research sparks new insights on laser welding
02.05.2019 | National Institute of Standards and Technology (NIST)
From June 25th to 27th 2019, the Fraunhofer Institute for Digital Media Technology IDMT in Ilmenau (Germany) will be presenting a new solution for acoustic quality inspection allowing contact-free, non-destructive testing of manufactured parts and components. The method which has reached Technology Readiness Level 6 already, is currently being successfully tested in practical use together with a number of industrial partners.
Reducing machine downtime, manufacturing defects, and excessive scrap
The quality of additively manufactured components depends not only on the manufacturing process, but also on the inline process control. The process control ensures a reliable coating process because it detects deviations from the target geometry immediately. At LASER World of PHOTONICS 2019, the Fraunhofer Institute for Laser Technology ILT will be demonstrating how well bi-directional sensor technology can already be used for Laser Material Deposition (LMD) in combination with commercial optics at booth A2.431.
Fraunhofer ILT has been developing optical sensor technology specifically for production measurement technology for around 10 years. In particular, its »bd-1«...
The well-known representation of chemical elements is just one example of how objects can be arranged and classified
The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...
Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.
Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...
Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.
The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...
24.06.2019 | Event News
29.04.2019 | Event News
17.04.2019 | Event News
24.06.2019 | Event News
24.06.2019 | Agricultural and Forestry Science
24.06.2019 | Life Sciences