Enabling the uptake of large-scale additive manufacturing
Riccardo Tosi, senior research engineer at the MTC, identifies the barriers preventing future adoption of large-scale directed energy deposition in industry
Scaling-up additively manufactured parts using directed energy deposition (DED) laser-based technologies is an increasing area of interest for industry. Machine manufacturers and end users are now looking to invest in a new generation of additive systems that can produce parts larger than possible using conventional powder bed fusion (PBF) technologies. However, developing this approach to the point where it can be used reliably to generate high-value components will require a concerted effort.
Large-scale DED can be achieved by mounting lasers onto large platforms, such as large CNC machine tools, robots or gantries with adjustable tables. Powder or wire-fed material can then be deposited layer-by-layer over a large area to manufacture new components, or to remanufacture or repair existing large components. Features, including unique material combinations, can also be added to parts in order to tailor their geometry and properties.
At the MTC one of the machines we have installed for large-scale DED applications is a Trumpf TruLaser Robot 5020 system. It is equipped with a 3.3kW TruDisk laser, a Kuka KR 30 HA robot, laser heads from Precitec and Trumpf, and Autodesk’s PowerMill Additive software. As everyone else in the industry is currently doing, we are gradually increasing the size of parts that can be built using AM.
The challenges ahead
Despite the future benefits that can be achieved through large-scale DED, there is still work to be done in addressing the challenges, limitations and gaps required to make this technology available.
Current critical obstacles standing in the way of large-scale DED adoption can be related to the readiness level of the market, as well as an unwillingness or inability to adapt to the manufacturing of large-scale additive components.
The worldwide market for additively manufactured products and additive manufacturing services is expected to reach $11.7bn this year, and is predicted to grow to a record $27.3bn in 2023 – an increase of almost two and a half times in just four years. As such, it is difficult to establish a comprehensive understanding of the current DED market – at the moment PBF systems have the biggest share of the metal market, with the share for DED technology currently being limited.
Caution around investment is directly connected to the lack of certainty, standards, and qualification methods related to the certification of components. Without a qualification route, especially in sensitive markets such as space and aerospace, it becomes difficult to certify and qualify parts manufactured with DED methods. That said, standard entities and large enterprises with research and development budget are now trying to push the large-scale route through case studies and collaboration with experts in the field. The journey to a better understanding of using DED to make large-scale components is just starting.
A large-scale DED system used at MTC: a Trumpf TruLaser Robot 5020 system equipped with a 3.3kW TruDisk laser, a Kuka KR 30 HA robot, and laser heads from Precitec and Trumpf. (Image: MTC)
While it is recognised that DED is another form of advance or alternative welding, people qualified specifically in this process are needed to operate the laser equipment involved. Such skills will be acquired through the transfer of invaluable knowledge and self-acquired experience from qualified engineers to new recruits. There are few learning opportunities available in the current market, and this creates difficulties in employing qualified workers. More often than not, end users and research centres offer internal programmes to upskill their staff to enable the delivery of advanced equipment. Buying a laser system in-house means not only an investment in the machine itself, but also in the education and skills required to use it.
An important variable that connects all these points is associated with the lack of turn-key equipment – in analysing the current DED systems it is evident that no ‘push and go’ equipment is available. The reasons for this are mainly connected to the specific requirement of the desired parts, the optimised manufacturing processes needed, limitations with the software currently available for AM, and the need to certify parts once they are built.
Machine manufacturers, software companies, universities, research centres and material suppliers are therefore now collaborating to unlock the requirements needed to make this technology more stable. Explorative case studies are one of the drivers of this industrial revolution for large-scale parts. At this stage, the challenges of this technology can be faced with tailored components and applications. The technology readiness level (TRL) should be understood by its users and pushed to a higher level through a certified manufacturing process and robust and reliable platforms.
Present DED technology can be compared to the PBF systems of six years ago, which faced many obstacles to the production of reliable components.
Today, this technology is used as an alternative route to manufacturing high-value components creating huge benefits for industry. The barriers and limitations associated with DED technology should, therefore, be seen as opportunities to challenge, improve and achieve even greater outcomes for industry. It is clear that the manufacturing of large-scale high-value parts with different laser sources is generating interest, so now is the time to convert curiosity to commercial reality.