3D metal printing revolutionized with new technologies

LED instead of laser or electron beam.

LED-based Selective Fusion (SLEDM), that is, selective fusion of metal dust using high-power LED light sources, is the name of the new technology that a team led by Franz Haas, head of the Institute of Engineering at Production at TU Graz, it has been developed for 3D metal printing and has now applied for a patent. The technology is similar to Selective Laser Fusion (SLM) and Electron Beam Fusion (EBM), in which metal powder is melted by means of a laser or electron beam and formed into a component layer by layer . However, SLEDM solves two core problems of these powder bed-based manufacturing processes: the production of high volume metal components that is time consuming and the manual post processing that is time consuming.

Reduced production time

Unlike the SLM or EBM processes, the SLEDM process uses a high power LED beam to melt the metal powder. The light emitting diodes used for this purpose were specially adapted by Preworks, a lighting specialist from western Styria, and equipped with a complex lens system whereby the diameter of the LED spotlight can be easily changed between 0.05 and 20 millimeters during fusion process. This allows the fusion of large volumes per unit of time without having to do without internal filigree structures, reducing the production time of components for fuel cells or medical technology, for example, by a factor of 20 on average.

Tedious reissue is no longer necessary

This technology is combined with a newly designed production plant that, in contrast to other metal fusion plants, adds the component from top to bottom. The component is thus exposed, the required amount of powder is minimized and the necessary post-processing can be carried out during the printing process. “Manual labor, which is generally time-consuming and necessary with current methods, for example, smoothing down rough surfaces and removing support structures, is no longer necessary and saves more valuable time,” says Haas.

Fields of application and other plans.

A demonstrator of the SLEDM process is already being considered at the K-Project CAMed of the Medical University of Graz, where the first laboratory for 3D medical printing was opened in October 2019. The process will be used to produce bioresorbable metal implants, it is That is, preferably screws made of magnesium alloys that are used for bone fractures. These implants dissolve in the body after the fracture site has grown together. A second operation, which is often very stressful for people, is no longer necessary. Thanks to SLEDM, the production of such implants would be possible directly in the operating room, because “an LED light is naturally less dangerous for operation than a powerful laser source,” says Haas.

The second approach is sustainable mobility, that is, the production of components such as bipolar plates for fuel cells or components for battery systems. “We want to make additive manufacturing using SLEDM economically viable for electric mobility and position SLEDM in this field of research at an early stage,” says Haas, who will produce a marketable prototype of this 3D metal printer – “made by TU Graz. “- in the next development step: greater innovation in the university environment.

The SLEDM process was developed at the FoE “Mobility and Production”, one of the five foci of scientific research at the Technological University of Graz.

At the Graz University of Technology, several research groups are working on additive manufacturing processes. The Institute of Production Engineering and the Institute of Materials Science, Union and Training are working intensively on the creation of their own additive manufacturing laboratory, the [email protected]