The Future of Multifunctional Additive Manufacturing: Insights from Nottingham’s Richard Hague

Richard Hague has been a true pioneer in 3D printing over the past 28 years. He has written numerous papers on various subjects, such as 3D printing aluminum alloys, inkjet 3D printing, topology optimization, functionally graded lattices, and more. Currently, Richard is focused on multilateral 3D printing and creating fully functional devices with the technology. Richard is also the Director of the Centre for Additive Manufacturing (CfAM) at the University of Nottingham and has done significant work on improving and industrializing additive manufacturing. Additionally, he heads Added Scientific, which conducts contract research and commercializes 3D printing technologies. Recently, I visited Nottingham and had the chance to interview Prof. Hague about his work.

Given his extensive experience in 3D printing, I wanted to understand the major changes Richard has observed in additive over the past 28 years.

¨Clearly, the major change is the acceptance and developments that have moved the area from primarily a prototyping focus to the growing emphasis on manufacturing. This was significant as it then opened up all the opportunities for design freedom that have become the hallmark and, to a certain extent, curse, of Additive Manufacturing. Basically, if you’re only prototyping something, it still has to be designed for the conventional manufacturing process that is going to be used and all the ‘design for manufacture’ constraints that exist there (for machining, molding, etc.). If the decision is taken to use AM as the manufacturing process, then the design envelope is massively expanded. There are obviously design constraints, depending on the AM process used (so geometry is not entirely free), but it’s about as free as it will ever get with manufacturing. This opens up significant possibilities (part consolidation, lattices, topology optimization, etc.).

“The ubiquity of low-cost FDM systems (and to a certain extent, vat photopolymerization techniques) has also opened the area to many more people and companies. Many, if not most, manufacturing organizations (or at least the ones that will survive) now have at least some kind of 3D printing process in-house, or have the awareness and knowledge to use external providers. Twenty-eight years ago, the community was so small that it was possible to name virtually every company that owned a system, and they were very expensive – both processes and materials.

“Metal LPBF has probably come the furthest – it didn’t really exist that far back and was only enabled with the introduction of fiber lasers in the mid-2000s. But, because one is able to process metals that engineers know and love (SS316, In718, Ti64), this has encouraged the use of metal systems for manufacturing end-use products. This hasn’t really happened as much for the polymer processes, where there is still a relatively limited range of materials that can be processed.”

Hague makes some very good points. One often overlooked is how low-cost systems have made it easy for many firms to adopt 3D printing. The abundance of these systems in large firms has given them opportunities to try out and evaluate 3D printers in a low-risk way. But, what does Richard think are the biggest issues holding us back?

“We need more materials, and they need to be better tuned for the application. For example, polymer processes are still fairly restricted in the range of materials – the predominant powder-based processes are still pretty much limited to Nylon 11 and 12 (with some TPUs thrown into the mix). For many applications, these are great, as has been shown, but Nylon 11 and 12 do not work for every application, so more engineering-grade materials are required. However, whether this new range of materials will be limited to powder-based techniques only is another question. Though FDM processes have a reasonable range of materials and have come a long way, the lack of industrial scalability for these systems (as they are mainly single nozzle-based) means they will always be limited in what they can produce. This is one reason we have been working on ‘reactive jetting’ based technologies, where we exploit the two-component deposition of monomers and catalysts that polymerize in-situ or in a reactive powder bed to produce engineering-grade polymer parts (such as polyurethanes and silicones) at scale.

“The discussion on the range of materials is also massively complicated if we then consider the move away from structural to functional materials (both single and multi-material). For example, in pharmaceuticals, bio-compatible applications, printed biology, batteries, 3D electronics, etc., there is significant potential for AM to extend its reach ‘beyond geometry’ for the production of optimized, functional components. However, each of these applications is heavily dependent on the processability of functional materials (ideally functionalized in process). That will not be easy, but I think this is where the true benefits of AM will emerge.”

Ultimately, Prof. Hague is much more ambitious than many people. Most are just looking at simple components that work, while Richard aims to create functional components comprised of multilateral prints made through efficient processes. Single-step production of batteries and electronics might be far off, but are we close to 3D printing our cell phones?

“No single AM process is going to be able to produce the range of length scales and materials required for all the elements of a mobile phone (micro-electronics, battery, screen, case, etc.), so I don’t think that we’re going to be seeing a fully printed mobile phone any time soon. However, I do think that AM is not far off from printing functional components of the phone individually, as we’re seeing great developments in the processing of functional materials via AM techniques.”

I’m intrigued by the possibility of efficiently combining many processes to make various phone components. Imagine a highly efficient, mass-optimized battery, traces, and antenna structure, for example, customized to fit into any phone. We need to explore numerous combinations of technologies and how to integrate them moving forward. Richard concurs, noting that in additive manufacturing, researchers have always had to work together and be multidisciplinary. Such research can lead to innovations like 3D-printed electronic components. However, he believes limitations in co-deposition and in-process functionalization of materials will be a bottleneck. I asked Hague what he was most excited about.

“I think the most exciting applications are the ones that include function, rather than just cleverly designed structural parts. We’ve all seen what the design freedom of AM can produce, but for me, the ultimate in design freedom includes functional freedom – both in single and multiple materials. We are beginning to see great strides in ‘multifunctional AM’ being made in our lab and other labs around the world. There is really interesting work going on in a range of functional fields, from pharmaceuticals, energy storage and harvesting devices (solar, batteries, sensing), to 3D electronics and bio-related areas.”

This is indeed a very ambitious future. I had never really seen it this way, but looking at the emerging functional areas brings us to an exciting frontier. Beyond just simple parts, we can create devices, machines, functional surfaces, and the elements that power our world. We can now consider chemical reactions, engineered processes, and devices produced rapidly in a limited number of steps. I was so inspired after my trip to Nottingham; the idea of there being so much more out there brings a smile to my face.