Science and technology buffs are abuzz about the latest video presentation by USC professor Behrokh Khoshnevis. At an April 2012 TEDx event, Khoshenevis demonstrated how an entire house could theoretically be built in 24 hours using a giant 3-D printer. Don't hang up your tool belt just yet though. Robotic construction has been in the news for over a decade, and about all we have to show for it are the same short walls and little domes. Still, given the pace of innovation in 3-D printing technology, an automated building application should not be dismissed entirely as science fiction.
3-D printing produces physical objects from computer designs. It has influenced manufacturing in the automotive, medical, aerospace, jewelry, and eyewear industries to name just a few. 3-D printing is an "additive" fabrication process as opposed to the traditional "subtractive" one. Plastic, metallic, or ceramic composites are laid down by high-tech nozzles, and built-up in very thin layers until the object is fully-formed. Industrial-grade 3-D printers once cost several hundred thousand dollars, but prices are dropping. In fact, a class of mid-range and low-end machines is now available for the small business and consumer market. The ability for individuals to economically design and produce prototypes is expected to spawn a wave of entrepreneurs and would-be inventors.
One of the early leaders in the consumer class of printers is a company called MakerBot. Their latest Replicator printer has received excellent reviews, and the company website features some fun videos of 3-D printing in action. MakerBot is also behind Thingiverse where digital designs can be downloaded for free as .stl files and physically created on your personal 3-D printer. Even Jay Leno has gotten in on the game. In this video, Jay visits a commercial shop to scan and reproduce a part for his 1907 antique car.
Going from 3-D printing auto parts to whole houses is quite a leap. The size of the machine, the uncontrolled outdoor environment, and the requirements and sheer quantity of the medium are just some of the challenges. Nonetheless professor Khoshenevis has relentlessly pursued automated building for the last 20 years. He calls his process and technology "Contour Crafting", and he has received backing at one time or another from the National Science Foundation and Office of Naval Research, Caterpillar, NASA, and USG. A major breakthrough occurred in 2005 when a self-supporting, non-clogging, composite fiber concrete was created with just the right viscosity for 3-D printer nozzles. Since then, Khoshnevis and his USC-based team have made some slow progress, but full scale models and testing remain elusive. Khoshenevis says he will need a "few million" more in funding. The cost of the special concrete is not disclosed. Foundations and footings aren't mentioned either.
Other groups are utilizing concrete printing technology on a smaller and perhaps more practical scale. The Freeform Construction Project based at Loughborough University in the UK, has created custom architectural components in concrete which would be extremely difficult to form by traditional methods. The use of 3-D concrete printing to satisfy some of today's complex architectural designs seems a whole lot more plausible than automated whole-house construction.
However, as professor Khoshenevis says, if you can build a wall, you can build a house. He claims over a billion people live in sub-standard housing, and today's construction materials, resources and techniques are no longer sufficient to meet tomorrow's basic needs. Dramatic change is needed. So stay tuned. While you're waiting, the good news is that even if you can't put away your old tools, at least now you can print new ones.