ExOne CEO discusses new machines, materials and why 2021 is the year of binder jet 3D printing

“2021 is going to be the year of binder jet,” according to John Hartner at least, CEO of additive manufacturing (AM) company ExOne, a pioneer of that same technology which, though more than two decades old, in the last few years, has found itself under the AM spotlight perhaps like ever before. Why now? Well, Hartner believes it’s a combination of metal binder jet’s production readiness and sustainability promise but he’d also argue, ExOne has been ready for that for a long time.

“It’s always been the technology that was right for production,” Hartner told TCT earlier this month while reflecting on a year of launches and new material developments for the Pennsylvania-based company. “Through the years, we’ve been advancing it and because of that experience, it’s now ready. We’ve got the experience, we’re ready to scale and we’re not going to sit on our laurels.”

That experience Hartner refers to is two decades of AM development which have resulted in 10 metal 3D printing platforms, topped by the large-format X1 160Pro last year and a line-up of more than 20 qualified materials for its Pro series machines. Even set against the backdrop of the pandemic, which saw ExOne join additive’s crusade against COVID-19 with the development of a reusable, sterilisable metal filter for N95 face masks, last year the company debuted several new materials, launched its sand 3D printing network, and debuted an advanced 3D printer concept based on its entry-level Innovent platform with smart factory vision.

“I think we went into 2020 really positive about what the year would bring and then we had to respond to the pandemic. And we’re a global company so we had to respond to it across the world,” Hartner explained. “Certainly we did the right things to keep our employees safe and make sure our customers were safe, and focused on those core things. But the good news is we had done such a positive job of preparing a foundation […] and we’ve done some things with engineering modularity that allows us to innovate faster, allows us to innovate without thousands of engineers. So we were able to do that with new platforms, like the 160Pro, like the new materials that are coming out, and I’m really excited about what we were able to accomplish.”

Detailing binder jet’s key capabilities, including speed, cost effectiveness and material diversity, Hartner says sustainability is the feature he’s most excited about, particularly when it comes to additive manufacturing for production. It’s a topic that’s high on the priority list for many AM companies as the benefits of lightweighting, decentralised manufacturing and material usage place additive as, on the surface, the obvious green choice. But Harnter cautions we’ll only truly see the benefits of that as additive transitions away from its prototyping identity and into real manufacturing.

“However you define it, and you can get very broad, a lot of people have talked about 3D printing helping sustainability, lightweighting, and part consolidation, and all those things are true, but when you do it on a prototype basis, it doesn’t have the impact,” Hartner said. “When you do it on a production basis, which is now possible with binder jetting technology, that really helps us deliver on our vision of sustainable manufacturing without limitations.”

It’s a subject that ExOne says has intensified in focus under Hartner’s leadership and was further emphasised in the company’s recent joining of the Additive Manufacturing Green Trade Association, an organisation setup up by fellow metal AM company Sintavia in 2019 to promote the benefits of 3D printing as a sustainable technology. Speaking on the cover of TCT Magazine last year, Hartner shared how ExOne was busy working to develop end-to-end research that shows just how sustainable its binder jet technology is compared to traditional methods of manufacture. Affirming this, a research paper published last year on Metal Powder Recyclability in Binder Jet Additive Manufacturing specifically, showed binder jet to deliver an overall material consumption efficiency of up to 96%. In terms of that material use, Hartner says he’s always got a close eye on how much metal going into machines at its own adoption centres doesn’t go into the printed parts themselves, but says the figure continues to decrease each quarter.

“It’s not a nationalistic thing, it’s actually a thing for humanity for our planet to allow that work to be done closer to the customer so you don’t throw a bunch of stuff away […],” Hartner said, of the potential for decentralised manufacturing. “I think this message of supply chain resilience and de-risking the supply chain, that’s being talked about at the board levels. It’s not just green minded engineers thinking about it, the CEO is thinking about it, so all of a sudden, it’s becoming a topic for how they spend capital. Just to set expectations, I’m not saying the world changes overnight in one quarter. […] But I think we’re well positioned with our production adoption model to help these customers get there over the next few years.”

This year, a number of new binder jet machines are expected to arrive onto the market from the likes of GE Additive, Desktop Metal and HP, but metal binder jetting has been around for a long time. In 1998, machining and automation company Extrude Hone launched its first business unit focused solely on metal 3D printing. It led to the development of the industry’s first commercial metal binder jetting system using technology invented and licensed by MIT and eventually became what we know today as ExOne. The technology was seen as a niche process at the time, providing part densities of around 55-60%, but during a joint research project with an aerospace company back in 2013, in what ExOne describes in the upcoming issue of TCT Magazine as ‘cracking the code on binder jetting metals’,  they were able to take that part density to 97% post-sintering, meaning it was now comparable with metal injection moulding.

Niche as it was, Motorola was its first customer and the company has since grabbed a broad range of users from jewellery makers to research labs and industry, many with multiple machines now installed, and partners like materials giant Sandvik, which is working to optimise metal powders.

“There’s no major automotive company that we’re not doing business with, in some way, shape or form right now,” Hartner said on ExOne’s customer base. “What I look at is how we’re working those customers through that adoption model [Ed: a five step process designer for successful implementation of binder jet] so that they understand what they’re getting, we understand what we can deliver, and we get to a point where we get to a success in the in the final marketplace.”

The latest addition to ExOne’s line-up, the InnoventPro, is said to bridge the gap between the research focused Innovent+ platform, the machine with ExOne’s largest binder jet install base, and the X1 25 Pro, promising print speeds topping 700 cc/hour. For larger production volumes, ExOne launched its biggest metal binder jet machine to date in the form of the X1 160Pro which features a build volume of 800 x 500 x 400 mm and even higher throughput of 10,000 cc/hour. Hartner likens the choice of machine platforms to buying a car, it’s not about choosing the most flashy or fast, it’s about selecting one that fits your needs: “The reality is I want something that’s going to do the job and most manufacturers want that. I think that’s where our product range fits.”

The goal is to give users an easy route to scale up their R&D to high-volume production. With this in mind, ExOne has also built modularity into its machines, deploying with the same recirculating print head and processes across its systems to broaden its materials palette and allow easy swapping of powders. Last year, the company established a three-tier system for qualifying new materials including third-party qualified, customer-qualified, and R&D qualified specifications which indicate market readiness. It’s also fast-tracking new materials such as stainless steels, Inconel and most recently, aluminium in response to market demand. Earlier this month, ExOne announced a deal with US Department of Energy’s Oak Ridge National Laboratory (ORNL) to 3D print parts in aluminium-infiltrated boron carbide (B4C), a material said to be suitable for neutron scattering research applications such as collimators, neutron imaging components and energy absorbing shielding equipment.

Reflecting on those materials advancements and production adoption model, which starts with identifying if a part is even right for binder jetting (ExOne recently launched an online calculator to expedite this decision in terms of cost), Hartner says it all ties in to ExOne’s larger vision: “I got here two years ago, we picked our vision with sustainable manufacturing without limitations, without limitations of materials without limitations of volumes and scale, without limitations of where you want to do it. If you want to start out us making you parts, before you get to your machine, we’re ready to do that right now. I think that’s a super exciting thing.”

While Hartner repeatedly assures that ExOne is ready to go in each of these key areas, one aspect that still remains future facing is its recently unveiled Industry 4.0 vision. It sees a future where multi-3D printer led production setups will be facilitated by Automated Guided Vehicles that transport parts all the way from the build process to final sintering. ExOne issued its own X1D1 AGV unit which will work in tangent with its ExOne Scout app, built with Siemens MindSphere, to deliver full time monitoring of each print job. Hartner says this vision will address and automate what he calls the “dirty secret” of multiple pre- and post-printing steps required in producing a finished 3D printed part, and while it’s available now to be deployed on a high volume basis, he added that we’ll see more from this in 2022 and beyond when manufacturers really start to scale their binder jet facilities.

“We’re grounded in reality, this market is growing, but it’s not such a rocket ship,” Hartner concludes. “Everyone’s going to project their future differently, all I can say is, we feel very strong about good growth in the market, and as those customers get those machines in, particularly the 160 Pro, that’s where multiple machines are going to make a huge difference in their lives and our lives in the future.”