Researchers at Massachusetts Institute of Technology’s Media Lab have built a prototype of a 3D printer large enough to build a 12-ft.-tall dome that is 50 ft. in diameter and fast enough that it did it in 12 hours. The printer is mounted on a tracked platform, so it can move around and be repositioned while it builds a structure, so there are no traditional limitations on build size or build envelope. The tracks lets the printer transport itself to remote and isolated areas across rough roads, much like a tracked military tank gets around.
The “printer,” known as the Digital Construction Platform, consists of a large robotic hydraulic arm fitted to a converted truck. At the end of the hydraulic arm is a smaller robotic arm—maybe finger is a better term—powered by photovoltaic cells. The smaller arm gives the device more agility and dexterity for creating structural details.
The device can vary the density of the material it is applying, letting it build tapered walls or an overhang, all to standards of building codes. The device can also mix materials, such as soil for building a compressed-earth structure, or concrete for building more conventional structures. The finger can be removed and replaced with other tools to support activities such as excavation or milling.
Researchers at MIT enlarged the standard 3D printer, let it work with a variety of construction materials, mounted it on a tracked platform, and dubbed it the Digital Construction Platform.
For the first test, the researchers had the machine build polyurethane foam blocks commonly used as forms for concrete construction. The blocks are filled with concrete to form walls, and interior and exterior elements are attached to them. The material cured in 30 seconds and the forms were completed in 14 hours.
The hollow foam blocks are filled with concrete to form walls, and interior and exterior elements can be attached to them. Keating says the material cured within 30 seconds and the entire test was complete in 14 hours.
The team also brought in local contractors to monitor the construction and ensure they were using existing construction-ready materials and meeting standards. This was key to attracting funding. Its initial success, for example, has already attracted firms such as Google and Autodesk, which are contributing money and space for further development.
Principal researcher Steven Keating says they could make the DCP smarter and fully self-sustainable. They could add sensors to make measurements and determine the best places to put in windows based on site-specific locations. Ground radar could determine the best place to put in the foundation, and the printer can form walls of varying thickness for insulation based on direction. Southern walls, for example, may get away with a thinner wall than those on the northern side. And walls could be tapered based on load-bearing needs.
Here’s the DCP in action, building a 50-ft. diameter concrete dome.
The platform’s ability to work with a variety of different material makes it attractive for use in the developing world, isolated areas where traditional building materials are cost-prohibitive. “It can excavate soil and with some fiber make a compressed earth structure,” says Keating, and its size lets it work in tight spaces.
“There are all sorts of novel possibilities,” Keating says. For future space exploration, it could work on Mars using soil and ice.
How far away the system is from commercialization has yet to be determined. Keating says the next challenges are to find enough funding to perform large-scale research on larger buildings. “Size and scale will take a long time,” he says.