In the 1960s and 1970s, NASA spent a lot of time thinking about whether toroidal (donut-shaped) fuel tanks were the way to go with its spacecraft. Toroidal tanks have a bunch of potential advantages over conventional spherical fuel tanks. For example, you can fit nearly 40% more volume within a toroidal tank than if you were using multiple spherical tanks within the same space. And perhaps most interestingly, you can shove stuff (like the back of an engine) through the middle of a toroidal tank, which could lead to some substantial efficiency gains if the tanks could also handle structural loads.
Because of their relatively complex shape, toroidal tanks are much more difficult to make than spherical tanks. Even though these tanks can perform better, NASA simply doesn’t have the expertise to manufacture them anymore, since each one has to be hand-built by highly skilled humans. But a company called Machina Labs thinks that they can do this with robots instead. And their vision is to completely change how we make things out of metal.
The fundamental problem that Machina Labs is trying to solve is that if you want to build parts out of metal efficiently at scale, it’s a slow process. Large metal parts need their own custom dies, which are very expensive one-offs that are about as inflexible as it’s possible to get, and then entire factories are built around these parts. It’s a huge investment, which means that it doesn’t matter if you find some new geometry or technique or material or market, because you have to justify that enormous up-front cost by making as much of the original thing as you possibly can, stifling the potential for rapid and flexible innovation.
On the other end of the spectrum you have the also very slow and expensive process of making metal parts one at a time by hand. A few hundred years ago, this was the only way of making metal parts: skilled metalworkers using hand tools for months to make things like armor and weapons. The nice thing about an expert metalworker is that they can use their skills and experience to make anything at all, which is where Machina Labs’ vision comes from, explains CEO Edward Mehr who co-founded Machina Labs after spending time at SpaceX followed by leading the 3D printing team at Relativity Space.
“Craftsmen can pick up different tools and apply them creatively to metal to do all kinds of different things. One day they can pick up a hammer and form a shield out of a sheet of metal,” says Mehr. “Next, they pick up the same hammer, and create a sword out of a metal rod. They’re very flexible.”
The technique that a human metalworker uses to shape metal is called forging, which preserves the grain flow of the metal as it’s worked. Casting, stamping, or milling metal (which are all ways of automating metal part production) are simply not as strong or as durable as parts that are forged, which can be an important differentiator for (say) things that have to go into space. But more on that in a bit.
The problem with human metalworkers is that the throughput is bad—humans are slow, and highly skilled humans in particular don’t scale well. For Mehr and Machina Labs, this is where the robots come in.
“We want to automate and scale using a platform called the ‘robotic craftsman.’ Our core enablers are robots that give us the kinematics of a human craftsman, and artificial intelligence that gives us control over the process,” Mehr says. “The concept is that we can do any process that a human craftsman can do, and actually some that humans can’t do because we can apply more force with better accuracy.”
This flexibility that robot metalworkers offer also enables the crafting of bespoke parts that would be impractical to make in any other way. These include toroidal (donut-shaped) fuel tanks that NASA has had its eye on for the last half century or so.
“The main challenge of these tanks is that the geometry is complex,” Mehr says. “Sixty years ago, NASA was bump-forming them with very skilled craftspeople, but a lot of them aren’t around anymore.” Mehr explains that the only other way to get that geometry is with dies, but for NASA, getting a die made for a fuel tank that’s necessarily been customized for one single spacecraft would be pretty much impossible to justify. “So one of the main reasons we’re not using toroidal tanks is because it’s just hard to make them.”
Machina Labs is now making toroidal tanks for NASA. For the moment, the robots are just doing the shaping, which is the tough part. Humans then weld the pieces together. But there’s no reason why the robots couldn’t do the entire process end-to-end and even more efficiently. Currently, they’re doing it the “human” way based on existing plans from NASA. “In the future,” Mehr tells us, “we can actually form these tanks in one or two pieces. That’s the next area that we’re exploring with NASA—how can we do things differently now that we don’t need to design around human ergonomics?”
Machina Labs’ ‘robotic craftsmen’ work in pairs to shape sheet metal, with one robot on each side of the sheet. The robots align their tools slightly offset from each other with the metal between them such that as the robots move across the sheet, it bends between the tools.Machina Labs
The video above shows Machina’s robots working on a tank that’s 4.572 m (15 feet) in diameter, likely destined for the Moon. “The main application is for lunar landers,” says Mehr. “The toroidal tanks bring the center of gravity of the vehicle lower than what you would have with spherical or pill-shaped tanks.”
Training these robots to work metal like this is done primarily through physics-based simulations that Machina developed in house (existing software being too slow), followed by human-guided iterations based on the resulting real-world data. The way that metal moves under pressure can be simulated pretty well, and although there’s certainly still a sim-to-real gap (simulating how the robot’s tool adheres to the surface of the material is particularly tricky), the robots are collecting so much empirical data that Machina is making substantial progress towards full autonomy, and even finding ways to improve the process.
An example of the kind of complex metal parts that Machina’s robots are able to make.Machina Labs
Ultimately, Machina wants to use robots to produce all kinds of metal parts. On the commercial side, they’re exploring things like car body panels, offering the option to change how your car looks in geometry rather than just color. The requirement for a couple of beefy robots to make this work means that roboforming is unlikely to become as pervasive as 3D printing, but the broader concept is the same: making physical objects a software problem rather than a hardware problem to enable customization at scale.
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