There are some new entrants in the quest to 3D print buildings, and while they're capable of producing architectural-sized structures, they're impressively small.
The Minibuilders project features three small robots that work together to build objects much bigger than themselves. Quite adorably, teamwork is their greatest asset: by taking over from each other as the building requirements change throughout construction, they can print the whole thing from start to finish.
"It's small robots printing large-scale buildings," summarised Dori Sadan, one of the five founders of Minibuilders, when I spoke to him at the 2014 3D Printshow in London. The Minibuilders project came out of the Institute for Advanced Architecture of Catalonia, and the researchers have now printed a proof-of-concept structure that looks like a giant vase on-site. Sadan talked me through the process.
The first robot, Foundation Robot, shuffles around the footprint of the building on caterpillar-style tracks, following a pre-defined route and using a sensor to steer itself around the shape.
Like your standard 3D printer, it squirts out building material, which is made up of 50 percent marble powder and 50 percent polymer for a lightweight but strong substance, in layers. It's a similar idea to the 3D-printed castle playhouse completed last month, but made by robots rather than a giant-sized RepRap-type machine.
After that bot has printed 20 layers, in steps Grip Robot. While it works in a similar way, extruding material through a nozzle layer upon layer, it doesn't have tracks: It clamps on to the existing structure using four rollers, and slides around the edges of the same walls it's building. It also has heaters to help the material cure faster—you don't wan't a robot clinging to soggy walls.
Even with fast-drying walls, there's only so high you can go until a structure becomes unstable, and that's where bot number three, Vacuum Robot, comes in. This little dude perhaps has the coolest movement mechanism: it attaches to the side of the structure with a vacuum suction cup while driving around on tracks similar to the first machine.
Vacuum Robot's job is to reinforce the walls, adding in support material where its needed in freeform vertical lines, instead of horizontal layers. "You need to reinforce it because its a shell structure, so he follows a pre-defined pattern and then they are working together and they can get to any scale," said Sadan.
He explained that the team is now already improving the robots, researching and optimising new materials, and fine-tuning their software. I asked quite how large they'd be able to build.
"In our vision, everything—but it will take time," he said.
On their website, the researchers show how you can use several of robots of each variety at once to cover a bigger area, with one "supplier robot" pushing the print material through pipes to its smaller minions.
It's a compelling idea to take 3D printing large-scale, and not only because teams of robots crawling around skyscrapers sounds like the future. A main challenge to printing full-sized houses is that you need a 3D printer bigger than the finished structure itself, or else need to print the building in parts and assemble them together—which you could argue defeats one of the benefits of 3D printing in the first place. Whether or not Minibuilders are the solution, they provide a wonderful example of how an alternative might work.