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Fraunhofer ILT celebrates 25 years of 3D metal printing

A drone hovers in the sky above Fraunhofer ILT, filming the world from above.

It looks down at around 50 employees from the Laser Powder Bed Fusion (LPBF) department, who stand together and form the number 25. 

The anniversary of the basic patent is reason enough to dedicate a video clip to it: 'Twenty-five years ago, the group was much smaller. Back then, only one Fraunhofer ILT researcher was actively working on the project.' says Jasmin Saewe, head of the LPBF competence area at Fraunhofer ILT. 'In 1996, the patent for metallic 3D laser printing was filed. A good occasion to look back in the past and forward in the future at our technology.' 

Today, it has around 50 employees and students. 

Not only can the LPBF process produce complex functional components, but it does so economically and uses resources efficiently. The production costs depend less on the complexity of the component geometry and more on its volume. At the beginning, the special thing about the idea was to focus on materials with interesting applications, such as cobalt-chromium alloys for dental implants, and to adapt the process accordingly. Today, the LPBF process is widely used in industry – in turbomachinery and automotive engineering, aerospace and medical technology.

Wilhelm Meiners, Andres Gasser and Konrad Wissenbach, inventors of the process and the patent, were happy to attend the filming. They talk about the beginnings: 'In principle, we started with my part-time job,' says Meiners with a smile, looking in front of him at the very first LPBF machine of Fraunhofer ILT. Konrad Wissenbach, head of the department at the time adds, 'At first we called the process Direct Selective Laser Sintering (DSLS), which is not exactly accurate. Later, we called it Selective Laser Melting (SLM).' He believed in the process and, together with Meiners and Gasser, continued to drive the technology forward through tireless dedication and scientific know-how.

The inventors of the process, Wilhelm Meiners, Kurt Wissenbach and Andres Gasser, stand in front of a small transport trolley with the first LPBF machine.

The first, still functioning machine stands on the trolley in front of the inventors and Andres Gasser explains how it works. 'Layer by layer, the metal powder is applied by means of a scraper. In each of these layers, the laser beam travels along calculated paths over the powder bed. The metal powder fuses and the workpiece takes its shape layer by layer.' The film session is coming to an end and a few anecdotes are making the rounds, including those about the first visits to trade fairs with the then brand new process. 'They laughed at us back then. What do you want to do with that?' says Andres Gasser.

In 2019, the global metal additive manufacturing market, including system, material, and service revenue, is estimated to be around €2 billion. LPBF is now the dominant technology in the metal additive manufacturing market with over 80 percent.

Fraunhofer ILT currently focuses on developing additive processes, innovative exposure concepts and machines as well as integrating these developments into industrial process chains. The extensive equipment consists of different commercial systems and highly flexible laboratory systems developed in house. It bundles its know-how, also from the areas of laser beam source and optics development as well as process monitoring, to advance customized applications and innovations.

Various films run across the monitor; they also tell of the beginnings. A 3D printed hip implant and a first dental implant are shown. One of the first use cases at the time was in dental technology; today, the LPBF process for manufacturing implants is state of the art.

The layer-by-layer build-up process of LPBF reduces a three-dimensional manufacturing task to two dimensions. As a result, the process offers a number of systematic advantages compared to conventional manufacturing techniques such as primary forming or machining. For example, it can be applied to build complex cooling channels for the targeted temperature control of tools or integrate grid structures for lightweight construction applications.

Yves Hagedorn of Aconity3D GmbH – a manufacturer of machine tools for the laser-based 3D printing of metals – also came to the event. He reports on his startup: 'Setting up a company always involves a risk, even if the market is identified and the startup succeeds. For us, therefore, the support of Fraunhofer ILT has always been very helpful and reassuring.'

LPBF technology allows prototypes to be produced in small series with identical material properties in a very short time. The systematic advantage is the shortening of development times. Many iterations can be carried out with less effort, resulting in a shorter time to market for a new product.

Anders Such of MAN Energy Solutions also appears on the set. He demonstrates how 13 conventionally manufactured components are merged into one monolithically manufactured AM component. He cites the advantages of additive series production of the guide vane cluster of a gas turbine: 'In developing the component for series production, the process know-how of Fraunhofer ILT particularly contributed to the success of the project. Thanks to ILT, we were able to overcome key challenges such as the process-induced distortion of the blade edges, the near-surface edge porosity and to identify a suitable process for tool-bound post-processing of the flow surfaces.'

In order to establish LPBF as an industrial manufacturing process and to exploit the process-specific advantages described above in production, it is necessary to view the entire process chain in its entirety: from component design through process control and systems engineering to finishing.

Jasmin Saewe is now head of the Laser Powder Bed Fusion competence area at the Fraunhofer Institute for Laser Technology ILT.

This approach, integrating all aspects of the process chain, also forms the basis for an important future topic of Fraunhofer ILT. With regard to cycle-oriented production and the topic of 'ecological footprint,' the LPBF process is to become exemplary; the focus is on 'life cycle assessment.' A transparent assessment of ecologically and sustainably manufactured products helps industry and SMEs assume responsibility for people and the environment and position themselves on the market with a competitive advantage.

In another exciting future project, ILT is currently producing 'smart parts' madewith LPBF. Electronic components and sensors can be integrated directly into the part during the LPBF process; the layer-by-layer structure is used to place sensors inside the component. This manufacturing process enables users to monitor the component’s condition and performance in use and even predict of possible damage using AI, which prevents failures and at the same time eliminates the need for preventive replacement of costly components. 

More than 20 dissertations and 250 theses accompany the growing expertise in the LPBF competence field at Fraunhofer ILT

Jasmin Saewe, Simon Vervoort, Tim Lantzsch and Professor Sebastian Bremen as well as the management team in the LPBF competence field sort through dissertations and theses on the desk in front of Professor Constantin Häfner, Director of Fraunhofer ILT. He explains why: 'An important element in the work of our institute is the development of expertise. This is clearly visible over the period of our work on the LPBF process. Today, after 25 years, 50 employees are researching, working and consulting with and for industry. A very good example of how we accomplish our mission as Fraunhofer ILT.'In this context, Professor Häfner refers to the close cooperation with the Digital Photonic Production (DPP) research campus, just a stone’s throw away from his institute. 

The cameraman finishes off his work and films the new machine, which has a five-laser scanner head and is a current piece of high-tech from Fraunhofer ILT. Unlike in conventional processes, the process head here is moved over the powder bed along with a local flow of protective gas. This allows the build-up rate and component size to be scaled up by a factor of up to ten. This innovative LPBF system offers a very large, effectively usable installation space of 1,000mm x 800mm x 500mm. Economical machining of entire turbines and aerospace components, for example, is within reach.

At the end of the shooting day, the camera drone hovers once again over the forecourt of Fraunhofer ILT. Now the 50 employees have gathered in front of the main entrance of their institute.

Once again waving behind the drone .... 

Article provided by Fraunhofer ILT.