In today’s world of 3D printing, materials are now ‘the main concern’ says Dr Kate Black, chief technology officer of Meta Additive, a tech start-up pioneering binder jet technology.
We’ve come a long way from the days when the process of stereolithography, or ‘rapid prototyping’ as it was once called, produced “plastic trinkets that helped you to see how something worked”. Black is referring to decades-old, antiquated processes that created components layer-by-layer in acrylic, in a morbidly slow procedure that would leave visitors at trade shows less than spellbound. The results “looked good, but they couldn’t be used in automotive or biomedical applications. But as time has moved on, people are now starting to focus more on the materials themselves. It doesn’t really matter what type of additive processes are used – and there are many; we’re still limited by materials.”
Which is why, says the materials scientist, “what we do at Meta Additive is take materials first. There have been lots of great engineers working on wonderful machines, but what’s missing is looking at the materials that go into the printers.” She explains how the operation in Stoke-on-Trent is working with a technology called binder jet printing, which employs an inkjet head (“just like the one you use at home to print on paper”) that “instead of printing out colours, prints a binder or glue. It’s been around for the past 20 years, but it’s got lots of downfalls, which is why it hasn’t been taken up by aerospace or automotive.”
The main problem, Black explains, is that while the printing itself is fast, this needs to be followed by a lengthy heat-treatment phase to remove the polymer glue that gets mixed in with the complex geometry of the part. The heat causes two problems: first there is that of shrinkage and distortion, while the second is of structural integrity: “once you’ve removed the glue, you’re left with holes,” she notes. These issues with the conventional ‘sacrificial’ polymer binder process “are what’s stopped it taking off in a meaningful way. There’s been lots of hype saying that 3D printing will take over manufacturing and we’ll only ever have 3D printers from now on and they’ll all be in everyone’s homes. But that’s simply not reality.”
In the world of 3D printing, materials have become the main concern, “and there’s a lack of understanding in this area of the field. Everything else is already in place. So instead of using a sacrificial polymer, at Meta Additive we use a functional binder made up of metals or ceramics arrived at from a chemistry background. There are no polymers in it and that’s where the innovation is. When you tell people that, they look at you and ask: ‘so where are the polymers?’ What we have is a dual-function binder that binds the powder in the powder bed – be that a metal or a ceramic – and infiltrates the powder bed with build material. Before, you were infiltrating the bed with polymers, which are not build material.”
Black says that coming at 3D printing from this organometallics angle – “that’s been used in many different guises, for many different applications all over the world” – has allowed Meta Additive “to create innovation”. She adds that it is the combination of organometallics, powder bed and the nano and micro metal and ceramic particles in the Meta Additive binder, that “adds the novelty. It’s a mindset. It’s a different approach to manufacturing. This is because if you solve problems as they arrive, one after another, yes, you will incrementally improve. But if you start with a solution and work backwards, you fix problems for good, rather than spend your time fighting fires. And our binders fix all that.”
At this point Black emphasises that this change in approach is important because, with 3D printing’s roots in rapid prototyping, “so long as the form looked all right, nobody really cared what it was made from. The way I look on it is that the workforce involved with 3D printing is mainly made up of mechanical engineers,” the implication being that if you want to get any further in the discipline, you need to bring in research chemists to solve the issues of structural integrity, shrinkage and distortion. This, says Black, will in turn lead to mass additive manufacture, which is “an oxymoron, normally”.
By tackling materials, additive manufacture can become bespoke in the truest sense of allowing complex user-specified geometries to be coupled with application-specific materials.
“Without materials we have nothing in the world, and engineering will stay just in your head. Engineers who forget to think about materials will never be good engineers, because you need materials to make ideas a reality. We’re living on a planet where materials are scarce. Resources and energy are scarce. We need to be able to control materials at the molecular level to give us the physical properties we require when we manufacture the parts. That cannot be done with mechanical engineering: it can only be done by materials scientists, chemists and biomaterials people understanding what’s going on at the molecular level, so that’s when we build it up to the macro level, we get the materials and the multi-materials we want. That’s what the Meta Additive focus is.”
Black says it’s easy to understand the importance of software, machines and printheads, “but there is still part of the additive manufacturing ecosystem that’s missing. Lots of people look at the raw materials that go into the powder bed. Lots of people look at polymers and plastics that go into FDM [fused deposition modelling] printers. But when it comes to metals and ceramics, we need to approach these from a chemistry and materials science point of view,” which are the central functions of Black’s expertise.
Being an agile tech start-up spun out of Black’s research at Liverpool has helped, but the big news in terms of Meta’s ability to leave a mark on 3D printing materials commercially is its recent acquisition by the billion-dollar NYSE-listed multinational Desktop Metal.
As tempting as it might be to think that Black’s scientific career followed the boilerplate origins of inquisitive kid taking apart car engines and instinctively putting them back together without adult supervision, nothing could be further from the reality. Instead, she faced a challenging childhood of learning difficulties and undiagnosed dyslexia. “I didn’t come from a straightforward high-flying background, and it’s something I talk to students about. I’m dyslexic and I have a non-identical twin sister who is not dyslexic, and we were always compared. I knew I wasn’t great at school because I had a direct comparison with my sister. I struggled because I wasn’t diagnosed until I was 16. But my mum knew that there was something wrong because speech was difficult for me early on and the only person that could understand me was my sister, who would translate for me.”
This was back in the 1980s, and the school system in Yorkshire just “didn’t get it. They said I was lazy and stupid to my face.” Black reckons that despite her uncomfortable experiences she “wouldn’t change it for the world because that’s what made me who I am now. But I did struggle for a very long time, and at secondary school I got put into a classroom called Room 3, and everyone knew that this was for remedial kids. I shudder to think that things like that happened back then. But they did. I had two options: I could show up on time and the other kids would shout ‘dunce’ at me. Or I could hide in the toilets and arrive late. I remember thinking that this was obviously wrong, and I knew that I didn’t belong there.”
Finding herself at the age of 16 with the literacy skills of someone half her age, Black still hadn’t read a book from cover to cover. “I’d go to an educational psychologist, and I managed to scrape through my GCSEs, and I got to do physics, chemistry and music A-levels”, the last of which reveals a creativity that might have taken the piano and saxophone-playing scientist down a jazz career – her late elder sister was a professional singer with English National Opera – if a place hadn’t become open at Bangor University. But science suited Black because, “unlike with exam conditions, whenever there was something practical to do, I did well. But unfortunately everything was measured by exams and so they’d give me extra time, which to a dyslexic person is even worse.” Bangor was at the time an academic centre for understanding dyslexia and welcomed Black to their establishment, where she got a third in chemistry (while getting firsts in her practical coursework). But she was to be supported by teaching staff who could understand the discrepancy between her ability in science and her inability to write it down. This led to a post-graduate degree, “which I did better at because half of it was lab work”.
Back in Yorkshire and on the dole, all Black knew was that she wanted to be an academic, because “I loved learning”. A stint as a research associate at the Centre for Advance Photonics and Electronics at the University of Cambridge didn’t quite live up to expectations for all concerned, and before long she joined the University of Liverpool as a lecturer in the Centre for Materials and Structures. She is also a member of the UK’s EPSRC Early Career Forum in Manufacturing Research. In 2018 Black was voted in the Top 50 Women in Engineering by the Women’s Engineering Society and the Daily Telegraph.
Meta Additive’s appearance happened over a few brief but eventful years. Back in pre-Covid 2019, Black was a full-time academic at the University of Liverpool in the School of Engineering, where she taught mechanical engineering and was conducting research into 3D printing. “Prior to that, I’d done a background project to prove the concept of the technology that Meta Additive is based on, and we secured IP in that.” This was when she approached additive manufacturing industrialist Simon Scott (who is now CEO of Meta Additive), “and I said that I thought the technology had legs and would like to take it out of the university environment and change the way that we do manufacturing”.
The two joined forces to form the start-up with what Black describes as “brilliant timing” – post-Brexit and just prior to a global pandemic, “but we like a challenge”. The restrictions ushered in by coronavirus brought with them the unexpected consequence of “slowing our competitors down because they were bigger organisations. But there was just me and Simon, which meant that we could keep pushing forward, moving from my labs in Liverpool where we built our first 3D printer. Although I come from a chemistry angle – that’s where the magic happens – we still needed machinery. And because of the pandemic we moved out of the university to Stoke-on-Trent and into Sutherland Works where we are today.”
The choice of location was important because for Black, despite working with what she calls “great revolutionary technology”, the Meta Additive story isn’t just about shiny metal. “We never wanted to be in a glass box on the edge of a science park. By their very nature, they’re nondescript. We are where we are,” she says, referring to the bottle kilns that make up the core of Meta’s premises, “because it’s about culture too. You can’t do what we do in a glass box.”
Black describes herself as “a firm believer in the idea that all the bits of science and technology that exist, scattered around the corners of the globe, are like pieces of a huge jigsaw puzzle. These are brought together by people, and that’s what creates innovation. That’s how you solve the 3D-printing problems of density, shrinkage and multi-materials.”
Source: E&T
