Q&A: How Markforged engineered a 2x print speed improvement in its PX100 metal binder jet machine

by Sam Davies

11 May 2023

10:42

Markforged

At last year's RAPID + TCT, Digital Metal announced the launch of its DMP/PRO binder jet 3D printer, which was described by the company as a 'complete binder jet solution.’

Within two months of that new product reveal, parent company Höganäs had taken the decision to sell off the Digital Metal business to Markforged, who was keen to expand its 3D printing hardware offering beyond the extrusion capabilities it had brought to market through its Desktop, Composite and Metal portfolios. "Markforged is not an FFF company," Markforged VP of Marketing Michael Papish told TCT, "we are a company that wants to help manufacture, and so we will use any technology that we think looks applicable and can help solve problems."

Fast forward to the next RAPID + TCT event and Markforged was showcasing the capabilities of its newly acquired binder jet technology from its stand. Since rebranded, the PX100 did not just don a fancy new name, but it also boasted some significant hardware improvements that, Markforged claims, would quicken the print speed and heighten the part quality.

At the event, TCT caught up with Markforged Global Metal Product Manager Ross Adams [RA] to understand how Markforged has been able to achieve such enhancements, where the technology will have the most impact, and the product strategy moving forward.

RA: Yeah, so, pretty big moment because this is the first time that this machine has been brought into the United States. Also, it's the first time that Digital Metal and Markforged has really had a joint presence [in front of a] wide manufacturing audience. Digital Metal has been doing binder jet for over 20 years now and they were previously very focused on making parts rather than making machines because they're run by a metal powder company, Höganäs.

Through the evolution of that, they realised that the future of this industry is supply chains, creating a competitive marketplace that ensures quality, ensures good economics, rather than a single source supplier. So, they saw Markforged as the right partner to help push that next stage of their business at that inflection point of having a technology adoption that we could push into the market.

At Markforged, it was important for us to have the right tools to span the full range of manufacturing. What we're pretty strong at is the tools and fixtures, the spare parts and prototyping as well. But FDM was never the right technology to scale to tens of thousands, hundreds of thousands of parts in a given year. We identify binder jet as a really strong potential because it has the speed and that's the first order of challenges that we need to overcome. So, we have customers making serial production parts, 50,000 in a year, having conversations every day about hundreds of thousands and even millions of parts per year, like the industry is becoming more and more educated on the right tool for the job.

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So, we have speed, but we also think binder jet is very good because of the quality. As far as surface finish goes, [we believe this is] second to none of all the metal 3D printing processes. It's an important functionally for applications, but it's also important in the early stages where people scrutinise parts and look for things that are different. So, moving forward with the best quality part and help with that adoption cycle and material properties as well, very predictable, very repeatable. [That's] the benefit of standing on the shoulders of a mature industry, metal injection moulding, where a lot of standards have been created. This is just a new tool to leverage the science of sintering. So, we really understand sintering very well, especially Digital Metal, and Markforged. We’ve really been collaboration between our engineers and sharing knowledge across different segments of materials and engineering. You put those three things together, we see it as a new tool that is going to scale additive into mass production. And that's why I think about every single day, I wake up in the morning and my job is solely focused on this printer in the North America region. I really see my job as an equation, simple business 101, supply and demand. So we need to drive the demand, create applications, create use cases, but also create the capacity on the other end. I think a lot of this industry is going to shape out with contract manufacturers doing the volume production. So, it's a two sided equation, the capacity doesn't come with the demand, but once the demand hits, you've got to have the capacity. And once we get some momentum, I think it goes mainstream.

RA: Digital Metal in Sweden, they still have their part production business, but they're offloading that business right now. We want to be focused, and it's hard to have one one foot in, one foot out. In our sales process, it is common that we need to print parts as proof of concept. So, we do have that ability through Sweden, we also have two customers in the United States that we use for that business. It's essential. For me, my job is really to ensure I understand the customer's requirements and make sure that our capabilities can match it. I think we have always had that type of consultant approach in our sales process that we don't want to sell you a tool that's not the right tool for the job.

RA: The key advantage in this new product is that we're doubling the print speed. And the way that we've achieved that is with the inkjet printhead. It used to have to do a snake pattern to cover the build volume. Now we're page wide, so it just passes by once, deposits all the ink, so it's like 2x improvement in speed from that. But aside from the speed, there's the production environment, just making the same part the same way every single time, 24/7. So, we really have optimised the machine design for quality, reliability, repeatability, those are three tenants that you need.

There are some key design decisions that I like to talk about with this printer and how we achieve that. The first one, you see this granite base on the top platform, we've found that was very important when dealing with loose metal powder that you have mechanical components move in, creating vibration, we want to dampen that as much as possible to have a really solid base that gives that weight to keep things from vibrating and shifting. The other one is the linear motors. Some other alternatives to that design would be like a rotary motor and a belt and pulley, but there you have tension, you have mechanical losses, and you have accelerating. So, if we're just travelling linear direction, we're going to use linear motors, they're more expensive but very fast acceleration, very steady state, in like a one-micron positional tolerance. Then the third thing is air bearings, which are basically on the sides of the carriage that moves. So, it goes on the top and goes on the side. If you’ve played air hockey before, it's the same concept where it creates an air gap of five microns, so this carriage is actually loaded, as it's travelling across it's very low friction but more importantly, going back to loose metal powder, it's got to find its way into places, whether you like it or not. If you're using ball bearings, and the metal powder finds its way into that ball bearing, you're going to get friction. You might be able to get good results on Monday, but production is Monday, Tuesday, Wednesday, Thursday, Friday. By the time you get to Friday, unless you spend hours and hours of maintenance in between each build on the machine, you're not going to get the same results. So, we really didn't make any compromises when it came to precision machine design. It took a lot of lessons learned from CMM tables, and really high-end CNC machines to strive to hit that production quality that we know is critical for our customer base in these applications.

RA: So basically, anything that you can sinter is going to be capable on this. We have ten qualified materials in our portfolio. Probably the most popular ones are going to be our stainless steels, 174 and 316L. [They have] good corrosion resistance, good strength, very good general properties. 4140 low carbon steel is another common one too [for] a lot of drive train components in engines and things like that. Some more specialty materials would be titanium Ti64 as well as pure copper. And then some super alloys like Inconcel 625, 718 and Mar 247, [which boast] high heat, high corrosion. And then two tool steels, H13 and D2.

We qualify our materials. So, we can basically guarantee the results if you're using our materials in the system but we also understand production. Sometimes, you want to have your own source materials so that you get more competitive pricing, or more specialty materials developed for a specific application. So, we do assist customers in developing their own materials if they have a very specific type of project that they want work on.

RA: First thing is education. Customers, it's a natural evolution of a new technology that they need to start shifting the way that they think of things, design for the process, find the right applications that really hit the sweet spot, not 3D printing for the sake of 3d printing, but 3D printing with the intention of having some type of improvement whether it's cost or performance.

There's also the angle of supply chains and being able to decentralise, now you can keep a warehouse in different stock items. I think sustainability is gonna play a big role as well. The fact that we can recycle all the powder that isn't used as well as to be able to lightweight more parts. One of my favourite quotes is, 'a small change multiplied by millions becomes a big change.' And in this technology where we're focused on mass production, a small change in using less material can have a significant impact. So, education is definitely a big thing.

I'll say there's a healthy amount of competition within this industry. And competition is a good thing in the capitalism market where we want to have the best solution. What that means is the best quality, which is what we strive for in the first order. And then secondary order will be speed and cost. And those three things need to come together. It goes back to that equation, drive demand, create capacity. And that's really what I wake up every morning thinking.

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RA: Some of the best markets that we're seeing success in today will be medical devices. A trend there is non invasive surgeries, making very small incisions and painkillers, and that's a really inspiring case to me. The geometries on these little grippers are just so compact, so intense, it's exposing the limitations and constraints put on us with traditional manufacturing.

Automotive is another key market for us. There's the accessories, the interior components, and then there's the under the hood, engine components. We're working both ends of those markets. The engine components will take a longer time because they're more critical in their function. I think the accessories is a different pursuit, you need to 3D print them. These markets don't exist without additive manufacturing, because there's no fixed tool involved in this process. So, I think where automotive is heading is more personalised customer experiences and having a good consumer experience when they're having input into the car that they're buying and being able to say, 'I want my initials on that shift knob, I want to have stainless steel polish with this cool pattern on it.' It creates a stickiness in that pre sales environment and that's gonna become a competitive advantages in the future.

And then there's the contract manufacturing side of things that create the capacity side of the equation. Everyone knows 3D printing is great prototyping tool. I think we need a different word for the type of prototyping that you can do with this printer. And I'm using the phrase 'pilot production' where, in a design process, there's some key milestones where you deliver one part, deliver 1,000, you deliver 10,000. In between each milestone, you're changing the design, you're improving it, you're getting the rubber to meet the road and starting to get that feedback. So, since they're always changing the design, and the expectation is lead time weeks not months, the velocity that these contract manufacturers are moving at is gonna become a competitive advantage to win more business for them. So, it's a very complementary technology to other services that they provide. What we see with like metal injection moulding being more the legacy process, there's a curve, the intersection point is basically 20,000 parts or less where cost per part would be cheaper with binder jetting because you won't have the tool. And when you get above that, it's a question of geometry and complexity.

RA: The most obvious one is going to be more materials and more applications, more industries and help have the right type of properties. One of the lesser thought about advantages of 3D printing isn't just the geometric complexity but the difficult materials that work with the traditional manufacturing. So, we're gonna continually invest in those areas and work with customers to really have a strong product roadmap of how we prioritise our efforts. I think in the more short term, we'll be looking less on hardware improvements to the printer, but thinking more about the full system, and finding ways to automate more processes, reduce the amount of human intervention that can have human error incorporated into it and really maximise the yield. Software is gonna play a big role in that. And that's definitely a big key area of Markforged's business, we've developed all of our own software and expertise. Because that's digital manufacturing, right? And that's the trend, going from analogue to digital, it's hard to prove in a pre sales environment the benefit of it, but then once engineers start using the technology and see the pace that they can move at, it's not something that detracts from their job and makes them more productive every single day.

by Sam Davies

11 May 2023

10:42