Meta Additive is the latest commercial company to enter the binder jet 3D printing space, joining the likes of ExOne, GE Additive, HP, Desktop Metal and Digital Metal. Spun out of the University of Liverpool in the UK, the company was co-founded by Dr Kate Black (CTO) and Simon Scott (CEO) with the ambition to move binder jet technology forward as a series production technology with a focus on chemistry.
Dr Black’s research at the University of Liverpool has its roots in atomic layer deposition (ALD) and chemical vapour deposition (CVD), before gradually moving towards binder jet via 2D inkjet printing. This year, Meta Additive is hoping to complete the commercialisation of the results – what the company is calling ‘reactive binder jet printing’ – and so we caught up with Dr Black to learn more.
Hi Kate, could you explain how Meta Additive’s reactive binder jet printing technology works?
Dr Kate Black [KB]: The idea is instead of using a sacrificial binder that needs to be debound and causes implications with density and shrinkage, can you bind and simultaneously infiltrate? That’s really where Meta’s technology stems from. So, there’s no polymers in the binder, there’s no sacrificial part of the binder, it’s all build material because it’s really about tackling AM through the chemistry of materials. Can you control and tailor chemical materials at the molecular level, so they give you the properties you want?
How is it different to things like ExOne and Desktop Metal? Well, they essentially rely on having nanoparticles in there, but there’s still a lot of unused, unwanted sacrificial material with both those systems, whereas the Meta system, it’s not really about the particles, but more about what we call organometallics. These chemistries that came from ALD that we’re using in 3D, they’re redesigned so that when they see a powder bed, they react to form a conformal coating of metal or ceramic that’s enough to loosely bind it together. But it’s not a bind resin in a polymer binder where they’re really fragile, when they come out of our printer, you can hit them over the table and they don’t disintegrate because there’s a natural reaction that’s going on hence the term reactive binder jet. Held within those chemistries are nanoparticles and micro particles and they fill in the rest of the pores and holes in the powder bed, so what you’re left with is a much a stronger green part – for want of a better word, it’s not really green, it’s actually chemically reactive – and then the heat treatment that you have is more of a consolidation step because there’s already that reaction. It’s just to make sure the microstructure is right.
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Okay, and what effect does that have?
KB: Right off the printer, we can achieve up to 88% density without any heat treatment and the shrinkage of the component is much more reliable. So, if you’re talking normal binder jet, it’s 20%, sometimes it can be even more than that. We’re looking at a 2% mark for shrinkage and that’s because you’re not taking all this material out of the powder bed.
But for us, where we’ll see the biggest benefits is this ability to process and control the material at the voxel level. You’re starting to see that in other processes, but the Meta process will allow us to graded structures, embedded functionality in there because you’ve got build material coming from the inkjet head and build material coming from your powder bed. So, the inkjet head has these solution components. This molecular component, that could be one material, then it’s got nano, which could be another material, it’s got micro, which could be another material and then the powder bed another materials. And you start to see how we can build up materials that perhaps have never been manufactured before, certainly not by AM before, and we can start to do graded materials and multi materials in one system. It’s got its heritage in binder jet, but there’s a lot more to it than that.
Meta Additive
What has been your motivation in developing this process?
KB: I was hearing from industry and academics that inkjet printing of metals was quite difficult to do because they had to do high sintering temperatures, which then stop them from being able to print of thermally sensitive substrates like plastic and paper. So, because the chemistry is coming from ALD/CVD, they’re naturally low temperature processes, that’s where we thought whether we could use these [chemistries] because when they see the powder bed or they see the flat substrate, they react at very low temperatures – I mean room temperature up to 100 degrees – and so that was why we did it for 3D, to say can we eliminate some of those processes so that we can maybe scale up for mass manufacture? And can we get rid of some of the issue that you’re seeing with binder jet parts, like shrinkage and density. Because the go-to AM for metal approaches is laser powder bed. Why has it not been used by lot of others? Well, it’s quite costly, it’s time consuming. And why do it that way when you could do investment casting or other mechanisms? Binder jet really appealed to me because, inherently, the actual printing process is quick. It’s all the post-processing steps that are the issue. And so, can we use chemistry to eradicate those issues? That was really at the heart of what Meta wanted to do.
If you broaden the palette of materials, just imagine what AM will be able to do. That will open up a whole new market. You’re then creating value rather than capturing value.
Could you elaborate on why and how chemistry is so important to what Meta is doing?
KB: The possibility of materials is far, far greater in this process than any others that I’m aware of. And that’s again because you’ve come across it from a molecular point of view and you can start to process complex alloys, hybrid systems. Can you do a metal-ceramic hybrid system? Can you grade through from a metallic to an oxide to a nitride? Because, essentially, an inkjet head is a glorified metering out machine, so you can control those materials on that voxel level of what you’re going to put in and because it’s got its heritage in ALD and CVD, many of these chemistries already exist. They’re just being applied for another technology. But the key for this technology is can we get this routine supply of the particles that we would require to service everybody? The main challenge for us is getting a routine supply of high-quality particles and that’s what we’re scoping at the moment. We received an Innovate UK grant in November for just over a million pounds. And that was really to scale everything up: scale the binders, scale the printers, because there's some great nanoparticle suppliers out there, but can they supply them on the quantity that we would need. If this was to go into all the sectors that it could, then it's hundreds and thousands of litres. There's a lot of material there.
So, what is the company’s approach in terms of developing the build materials?
KB: Our approach is to enter into evaluation periods with end users. What that allows us to do is to broaden our material offering, our binder offering, but it's also answering the needs and requirements of real end users. And being able to test our materials and our resulting printed components in an environment where the users want them. So, we have a couple of evaluation cases that we're dealing with end users at the moment from a whole range of sectors, but we are looking for others.
We do a 12 month evaluation period where we say okay at the end of the 12 months, you go away with this React 125 printer - 125 is the build area platform - but in the meantime, we'll work with you to develop a material system of your choice. So, say somebody comes to us and says, ‘right, we need a special aluminium alloy,’ we will develop that aluminium binder for them. They then go away. They've got a material system that suits their use, but they've also then got a printer. For the price of the printer, they get the printer, but they also get the evaluation and what do we get? We get good collaborations; we understand how the material systems work in end users’ applications. And we start to build up our material database.
With this materials approach and the capabilities of reactive binder jet technology, what do you see as the big opportunities for Meta Additive?
KB: I think it’s where we start to need much smarter solutions. We’re entering the stage of humankind where the manufacturing solutions that we’ll need to be able to meet these challenges are going to be far more sophisticated than the technologies we currently have. Existing AM goes someway to doing that, but there are two things limiting AM, the first being materials.
Meta will be able to eradicate some of those issues by broadening the palette of materials and that will allow us to give much smarter products to market. It’s like giving an artist a blue and a red compared to 56 different colours, what they’re going to design will be far greater than they do with the existing palette.
And then the second thing is about creating this additive manufacturing ecosystem that will be required to really unlock additive manufacturing. Let’s work with raw materials suppliers, the software guys, the machine learning guys, because if we’re broadening the palette of materials, you’re going to need the software that will be able to cope with that. The word that people use for additive manufacturing is bespoke, but what they actually mean is it’s bespoke in geometric terms, it’s not bespoke in material terms. If you broaden the palette of materials, just imagine what AM will be able to do. That will open up a whole new market. You’re then creating value rather than capturing value. And to be able to do that, you need to get all those pieces of the ecosystem or jigsaw puzzle together.
Every time the Wohlers Report comes out, it’s going to be this amount of billions [by year X], and we never quite reach that target. And I think that’s because we’re perhaps not using people’s expertise to the best of our ability.
And what do you think can come from this embrace of other disciplines and collaboration?
Meta Additive
Meta Additive's REAPT 125 machine.
KB: Everything about manufacturing is to do with the materials. If we don’t have the materials, it’s just an idea in your head, and it will stay an idea unless you have the materials. We’re seeing a lot of companies from a whole variety of sectors saying, ‘we need materials that do this.’ And then people go, ‘well, we’ve got this stainless steel one or this titanium one.’ They’re not thinking, ‘how can we push the boundaries, how can we start to modify those?’ I would say Meta Additive is a company that has materials at its heart. That’s its main approach to things, particularly on that chemical side and being able to manipulate and control materials at a molecular level, but it’s also knowing that we need other involved. Everything else needs to pick up speed, particularly in software and machine learning. I think there’s going to be a really big next step for additive manufacturing. You think about all the data that we’re currently collecting by all AM approaches, but what are we doing with it? Not much. And I think materials will take a big step if we start to combine those with the people already working in machine learning. I think all of these pieces to the puzzle already exist. It’s about how do we bring them in?
I think most of the disciplines that aren’t concentrated on the printing processes - software, materials, post-processing etc - feel as though their area is somewhat overlooked. Big strides have been made in the last few years, but there was an industry for 25 years before that. Why do you think that is?
KB: Because they’ve come from an engineering point of view. They’ve made some amazing machines, but just gone into bulk materials, it’s like shoehorning materials into a printer, or ‘can we modify the laser that we use or the wiper blades that we use?’ Yes, those things need to happen, but they only get you so far. If you don’t put those materials fundamentally at the heart of AM, then I just think that the progress is limited. That’s what we’re seeing the results of now.
Well, it was primarily a prototyping technology for a while, so I suppose there was less of a focus on materials for a long time.
KB: No, but it’s been called additive manufacturing for a while. There’s still a bit a bit of magic and mesmerising the Joe Bloggs on the street. We’ve got to get over that. And you go to Formnext, and you see all these metal parts and to our naked eye it looks great, but we all know that most of those can’t be used in real world applications. That needs to stop. We need to put some substance to it, I think. And that substance is about breaking down silos, people working collaboratively together. We need to have some joined up thinking, we also need to say enough is enough of the magic stuff and start putting some substance into the materials, and how can machines help to do that? If we get that right, the stuff we’ll be able to manufacture, nobody will have thought about a lot of the stuff that’s going to be possible in the next ten years.
Meta Additive is hoping to launch its first machine and metal binder in line with Formnext this November.
