LEDs for 3D metal printing

Materials World magazine
,
7 May 2020

Selective LED-based melting (SLEDM) is the new technology being put forward for 3D metal printing to reduce production times for components for fuel cell or medical technology. The technique, developed at Graz University of Technology (TU Graz) in Austria, involves targeted melting of metal powder using high-power LED light sources .

It is similar to selective laser melting and electron beam melting of metal powder, but SLEDM is said to solve two central problems – the time-consuming nature of producing large-volume metal components and the manual post-processing.

The technology uses a high-power LED beam that was 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 larger volumes to be melted, without having to dispense with filigree internal structures, thus reducing the production time by a factor of 20 on average for components for fuel cell or medical technology, for example.

This is combined with a newly designed production plant which – in contrast to other metal melting plants – is said to add 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 printing. ‘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 Franz Haas, Head of the Institute of Production Engineering at TU Graz.

A demonstrator is already being considered at the Medical University of Graz, where a laboratory for 3D printing was opened in October 2019. The process will be used to produce bioresorbable metal implants directly in the operating theatre, because ‘an LED light is naturally less dangerous for the operation than a powerful laser source’, says Haas.