I had some thoughts about the speed of 3DCP and how large buildings can be 3D printed quickly.
3DCP, or 3D Construction Printing, is the science of extruding concrete through a moving toolhead. Like a smaller 3D printer, 3DCP devices build objects (buildings or architectural components) layer by layer.
There have been many 3DCP projects around the world using this technology. Typically, the projects are single-story structures, often residential homes or small commercial structures, like bus stops or sculptures.
Rarer are taller structures. There are the occasional two- or even three-story structure, but almost never beyond that.
Now we see a report describing a project undertaken by ETH Zurich researchers who apparently have produced the “world’s tallest” 3D printed structure, the White Tower in Mulegns. It’s actually 30m tall, which is quite high and definitely higher than other 3D printed structures, at least so far.
How can you 3D print tall structures? There’s an immediate problem that’s due to the nature of concrete: it slumps. Concrete solidifies relatively slowly, so you can’t just speed up printing: the layers underneath must be sufficiently solid to continue.
There’s another problem. There are two types of 3DCP devices: gantry and robotic.
The gantry approach basically involves building an enormous Cartesian 3D printer to surround the structure, and print it much like a small FFF 3D printer would do. Therefore, the size of the object is limited by the size of the gantry system.
Robotic systems are different: they involve a toolhead on the end of a robotic arm. This means that the size of the print is limited by the reach of the robotic arm. And bigger robots are very expensive.
To overcome these limitations, the ETH Zurich crew used a different approach: assembly. Here, they would print concrete components at a central factory, which were then shipped to the build site. There, they were assembled into the final structure with cranes and workers affixing them together.
This is how large 3DCP structures will be built in the future. No one will build a gantry 3DCP printer the size of a ten-story building. No robots exist that can reach 100 m into the sky.
Assembly is commonly done in traditional construction as well. Pre-fab components are snapped together, sometimes quite quickly. Even without assembly, tall buildings usually involve pouring one floor at a time, allowing each to cure before moving up to the next level.
So how could this speed up construction? I believe this would be accomplished through parallel production. Imagine if the factory that produced the 3DCP components was actually a large farm of devices. Such an operation could produce a much higher throughput of components. A stream of components would then be sent to the build site, where assemblers could work as fast as the parts arrived.
The White Tower is a vision of how this is likely going to work in the future. Except instead of artistic towers, it will be skyscrapers we see rising into the clouds.
Via ETH Zurich
