Graz University of Technology has developed a technology that uses LED instead of laser sources for the additive manufacturing of metal parts and optimizes 3D metal printing in terms of construction time, metal powder consumption, equipment costs and post-processing effort. Selective LED-based melting (SLEDM) – i.e. the targeted melting of metal powder 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 Production Engineering at TU Graz, has developed for 3D metal printing and has now applied for a patent.
The technology is similar to selective laser melting (SLM) and electron beam melting (EBM), in which metal powder is melted by means of a laser or electron beam and built up into a component layer by layer. However, SLEDM solves two central problems of these powder bed-based manufacturing processes: the time-consuming production of large-volume metal components and the time-consuming manual post-processing.
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 the west Styrian lighting specialist Preworks and equipped with a complex lens system by which the diameter of the LED focus can be easily changed between 0.05 and 20 millimetres during the melting process. This enables the melting of larger volumes per unit of time without having to dispense with filigree internal structures, thus reducing the production time of components for fuel cell or medical technology, for example, by a factor of 20 on average.
Tedious reworking is no longer necessary
This technology is combined with a newly designed production plant which – in contrast to other metal melting plants – adds the component from top to bottom. The component is thus exposed, the required amount of powder is reduced to a minimum and the necessary post-processing can be carried out during the printing process. “The time-consuming, usually manual reworking that is necessary with current methods, for example, smoothing rough surfaces and removing supporting structures, is no longer necessary and saves further valuable time,” says Haas.
Fields of application and further plans, read more.