While enthusiasts believe that there will eventually be a 3-D printer in every home, University of Southern California professor Berokh Khoshnevis has spent the last decade working on a far bigger vision: a gigantic 3-D printer that can print an entire home—concrete, electrical wiring, plumbing, and all.
The idea of manufacturing homes using what essentially looks like a gigantic hot glue gun sounds crazy. But Khoshnevis and his students at the school's Center for Rapid Automated Fabrication Technologies have been tinkering long enough to have made major progress on designs and prototypes. His "contour crafting" robotic construction system has now printed entire six-foot tall sections of homes in his lab, after perfecting the difficult process of extruding concrete in a layered fashion. He can also use gypsum, wood chips, and epoxy, and is working on adobe materials.
"We have pretty much solved all the basic problems," he says. "We can build a whole house right now, but the only problems are those of logistics." The system uses robotic arms and extrusion nozzles that are controlled by a computerized gantry system which moves a nozzle back and forth.
Khoshnevis started working on the idea when he realized the gigantic opportunity in introducing more speed and affordability into construction: "It’s the last frontier of automation. Everything else is made by machines except buildings. Your shoes, your car, your appliances. You don’t have to buy anything that is made by hand."
Ultimately, he thinks he will be able to build a 2,500-square-foot home in 20 hours, though the first whole houses will probably be much smaller. One major application, he believes, will be in emergency and temporary shelters.
There could be big advantages to contour crafting in other markets, especially affordable and low-income housing. Khoshnevis imagines that places like Home Depot could one day stock and rent out the machines, allowing homes to be built more cheaply by reducing labor and material costs (the technique wastes less material than conventional construction, because the 3-D printer only prints what is needed).
As with all 3-D printing, there is an unprecedented opportunity to customize design—just upload a file and a computer will configure the rest. His prototype can print curved surfaces, for example. No more cookie cutter developments.
The logistics are, of course, not an inconsequential hurdle. Khoshnevis thinks that, once perfected, his method could reduce construction costs to 30% or 40% of what they are today. But it would take a major mindset shift to see affordable homes built by machine. Construction workers would be less than thrilled.
There are early initial applications. NASA has given Khoshnevis a grant to work on building lunar structures on the moon or other planets that humans could one day colonize. A major multinational firm has commissioned him to work on "specialized structures" that he’s not allowed to discuss.
You can see contour crafting in action in the video above, and watch Khoshnevis's longer TEDx talk from last year below.