Behrokh Khoshnevis has always known that 3D printing would make its biggest impact on big structures. While most advances in additive manufacturing technology have been geared toward producing objects of roughly bread-box size, Khoshnevis has gone macro, creating printers that could lay down the walls of a building in a day.
Khoshnevis built his first cement printer in the late 1990s, and since then he has been continually refining the technology. By 2014 his gantry system could conjure the shell of a small house in 10 hours. And the recipe for cement he developed allows it to emerge from the printer's nozzle smoothly and consistently but harden relatively quickly once laid. It held the promise of more sustainable construction, fast cheap houses for the needy, curvy organic shapes for architects, and a method for building on the Moon and Mars. The technology won him SAE's Create the Future Design Contest in 2014. That award, and another from NASA, eventually helped him secure funding for his business, Contour Crafting Corporation.
But after the initial promise, prototypes, and demonstrations, the road to making a viable product has been long. “Early on, there was a lot of excitement expressed — even from myself — about what this technology can do,” said Khoshnevis. “But you don't see significant numbers of buildings being built by this technology. The question is, why?"
The answer is multi-pronged. For one thing, a Contour Crafting printer prints only the walls of a home, so the economic benefits are limited to roughly 30 percent of the cost of construction. Also, the construction industry is famously slow to adopt new methods, and most building codes have yet to incorporate the technology. And it took several days to set up the printer before it went to work.
Khoshnevis's CrafTrans printer addresses this last issue. Rather than the traditional gantry of previous incarnations, the CrafTrans is a cantilever gantry robot with both rails on one side. It folds up, fits on the back of a standard 20-foot truck bed, and can be set up by a single person within half an hour. “You don't have to build a foundation for the rails, don't have to make a ditch and pour concrete in it,” said Khoshnevis. “With this method, everything is almost instantaneous.”
Contour Crafting teamed up with the city of Los Angles to build shelters for the homeless in 2020, but the project was put on indefinite hold, thanks to COVID-19. So, unfortunately, the only large-scale structures that have been erected with a Contour Crafting printer have been for demonstration purposes. “As I delve more and more into this, I begin to see that the world is not as simple as I thought it would be,” said Khoshnevis. “Maybe this naivety is good for inventors — if you saw all the challenges, you would give up at the beginning.”
Those challenges, as steep as they may be, haven't stopped the advancement of Contour Crafting. The Department of Defense has recently engaged Khoshnevis and his company to develop printers that will be deployable for emergency response. And oil companies have contacted him to use his printers where other types of construction are practically impossible.
“We are looking forward to the near future, to getting into the market and having a meaningful product and making a difference,” said Khoshnevis. “That's the motivation that drove me. I didn't just want to invent something. I wanted to make an impact.”
2014 GRAND PRIZE WINNER
INNOVATOR: Behrokh Khoshnevis, Founder, Contour Crafting
INNOVATION: A computerized construction method that rapidly 3D prints large-scale structures directly from architectural CAD models.
IMPACT: Affordable building of high-quality, low-income housing; the rapid construction of emergency shelters; and on-demand housing in response to disasters.
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