New space, new applications: Sintavia CEO on 3D printing and rocket construction


If the MakerBot Replicator was the poster child of 3D printing manufacturers’ movement, these huge custom metal laser sintering systems from EOS AMCM GmbH the company may be on its way to becoming the one in the additive manufacturing (AM) space race.

First adopted by the new space launch company Launcher to 3D print a one-piece liquid rocket engine in 2019, other modified EOS systems from AMCM, short for Additive Manufacturing Customized Machines, were acquired by the British company Orbex to accelerate its development – in-house capacity for the production of more than 35 large-scale rocket motors and main-stage turbopump systems per year, and more recently Sintavia, which took delivery of two M4K-4 systems this summer.

For the Florida-based metal AM provider, which focuses primarily on the aerospace and defense industries, it’s a journey that began late last year as customer demand for a A more optimized way of printing single-component metal parts on a large scale for the aerospace industry has taken off. Now, with two M4K-4 systems joining its ever-expanding line of AM equipment, Sintavia believes this new capability will be a North American first for commercial aerospace and space customers.

“As we have developed the company and grown, there has been a merger around certain categories of parts that are really good for the additive,” said Brian Neff, CEO of Sintavia, at TCT. “One of those categories is regenerative rocket thrust chamber (TCA) assemblies. This is an area where virtually 100% of all thrust chamber sets currently on the market are printed, including in more traditional designs. I think this was known as a really good part for additives because the operation of regenerative cooling is very similar to that of a heat exchanger with an internal passage circulating a very, very cold liquid propellant through a very hot chamber. . That’s a big part for the additive.

Sintavia’s current AM capability would be the envy of most engineers. With 30 high-speed printers in-house, including several from GE Additive, TRUMPF and, of course, EOS, including eight M400-4 quad laser printers, Neff explained how the company was already well-equipped with the necessary experience and strategies. to enter the rocket building arena. What they needed was to go further.

“The limitations that exist on today’s machines are that they just aren’t big enough,” explained Neff. “The way people have done it as an additive so far has been basically printing three parts and making flanges and welding them together. What the M4K allows us to do is fabricate each thrust chamber assembly as a monolithic part. So you can make the injector, the barrel, the nozzle in one piece, which is a complete game-changer. Every time you put two components together, you need to make a larger flange, which becomes a heat sink, which affects the performance of the rocket. You are not able to achieve certain cooling strategies inside the entire thrust chamber because you have to join them in post-processing, and everything has to line up perfectly. This is a suboptimal way to print these TCAs. With the M4K, I think it’s a game-changer, especially for the rocket propulsion industry, in the sense that you can go back and redesign your components to eliminate all kinds of flanges. It is really very important. “

Additive advantage

According to the AMCM, the Launcher E-2 engine’s combustion chamber was developed as an “AM-compatible combustion chamber from the start” to bring together advantages such as those described by Neff into a single structure. The same can be said of Sintavia’s customers with whom the company is now working closely to redesign parts to reduce assemblies and take advantage of the M4K-4’s 450mm x 450mm x 1000mm build capacity for TCA and other thermodynamic parts and fins.

“Right now we have a customer who prints a large four-piece heat exchanger,” Neff said. “Now we can do it as a single unit as long as you know how to extract the powder from the heat exchanger – that’s the key. We have developed ways to do it.

The M4K-4 has been described as a “stretched and widened” version of the EOS M400-4 due to its larger build capacity, more powerful lasers, and improved cooling system. Once installed, Sintavia plans to run the machines with high performance copper and nickel alloys. The similar architecture to the M400-4 means that Sintavia already has three years of hands-on experience with the platform to rely on. Neff offers an aerospace analogy that if a pilot is qualified to fly a 767 aircraft, they can also fly a 757 or the like. Of course, there are considerations to be taken into account due to the build scale. For example, AMCM explained to TCT how part deformation due to the high heat load during construction can be countered with precise simulation tools, but Neff is confident that Sintavia is armed to make it work for what has been. described as “overwhelming” customer demand. Notably, despite the disparity in market size, much of this innovation push comes from the space segment rather than aerospace.

“What we’ve seen is that the commercial space industry is driving the commercial aerospace industry towards greater adoption of additives, which is great to see,” explained Neff. “The commercial space industry, if you just look at the launch aspect, is still very small compared to commercial aerospace. Even with the parts we’ve made for this world, generally on the business aviation side at this point, we’ve historically seen very slow adoption. […] They see the way these rocket designers and rocket makers are looking at the additive and I think it’s created kind of a pull in the market and it’s really wonderful to see because I love the rocket industry. and I think it has an amazing future, but I think commercial aerospace is really such a big market that for us being a big player is really one of our goals. “

The decision to bring these new machines in-house was driven by demands from commercial space launch customers to create TCAs with fewer traditional assembly steps, to optimize regenerative cooling passages and, therefore, to reduce time and complexity. This combination of benefits, according to Neff, is crucial.

“As an addendum, you have to solve a problem,” explained Neff. “You have to do something better, faster or cheaper, all three, hopefully, to be successful. I think people in the industry are still, in a lot of ways, like, “Well, I can print this in a different way and that’s what makes it better.” No, what makes something better, is it faster or cheaper or does it work much better? In this case, our customers came to us and said, ‘we really want to get rid of these flanges, it takes time, we have to machine them, there is a weak point and it is sub-optimal of a flow point of view. ‘”

Taking a moment to think about the future possibilities, while Neff is keen to stress that using additives is about bringing together the right application and the right benefits, for companies like Launcher or Relativity Space that have the ambition to print entirely in 3D of entire rockets and engines, he thinks there is value to be found in looking beyond what we can achieve today.

“If you want to go a bit far, you won’t have a foundry on Mars,” Neff says. “You’re going to have to print everything out when you’re on Mars. I think when people say they’re really trying to think ahead of the curve. They think, well, when we are on other celestial bodies, even the moon, people will try to print with solar energy and moon dust and that will be the manufacturing technology that will be used. You’re not going to have that big, molten, hot metal cauldron that you pour into shapes and then waste all that stuff. You will be using 3D printing. I think when companies market in that direction, they also say to the market, “we can do it here and then we can do it up there in space”. I think that’s a really cool thing.

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