The automotive industry is well acquainted with 3D printing; it’s a common tool for prototyping, especially for parts and models. But Strati, designed by Michele Anoè, is the first drivable car with a wholly 3D-printed body.
A low-riding roadster with an open cockpit and an electric motor, the Strati glides at speeds up to 50 mph. Its dark features accentuated with red seats and white wheels give it a slick appearance. What stand out most, though, are the thick horizontal layers, visible leftovers of the fused filament fabrication process that makes the car unique.
Strati is just one offering from Local Motors, an unconventional Phoenix-based transportation company that combines cooperative design (they have a mandatory Creative Commons sharing policy) with micro manufacturing. But it’s the best example yet of what CEO and co-founder Jay Rogers says are Local Motors’ primary goals: speed up car manufacturing and address 3D printing’s greatest challenge — making useful, complete products.
“There is a fundamental difference between printing a beautiful object and saying, I just need a structure and I’m going to let a knife, or a mill, come along afterward and make it as functional or beautiful as I need it to be,” says Rogers. With Strati, Local Motors ignored the typical concern of high-resolution printing, opting instead for a fast process that produces a structurally sound body and then milling it to its final shape.
Strati was the winning entry in a competition for Local Motors community members. The designers didn’t set out just to build a 3D car, but to make cars easier to build. Their biggest target for innovation was to reduce the part count, from the tens of thousands in a typical car to just 49 in Strati’s case.
Into the body they placed the motor and components from a Renault Twizy. The result is undergoing crash testing and certification as a Neighborhood Electric Vehicle. Rogers expects Strati to be available for purchase within the
next year.
With the contest, Local Motors was encour-aging designers to adapt the design to the technology, says James Earle, an advanced manufacturing engineer for the company. Additive manufacturing has some restrictions that traditional manufacturing doesn’t (and vice versa). “The process really kind of informs the design,” Earle says. “When you increase the scale, there are other factors you have to ac-count for.”
He points specifically to thermal contraction — ABS tends to shrink as it cools, and a 10-foot print can shrink quite a lot. So they used plastic pellets infused with carbon fiber, which keeps it from shrinking as much, while adding stiffness and tensile strength.
All 212 layers are printed on a Big Area Additive Manufacturing printer from Cincinnati Incorporated, which has a 12’×7’×3’ bed. After printing, a 5-axis CNC from Thermwood does aesthetic machining and cleans up the mounting brackets. Finally, it’s assembled quickly, thanks largely to the small number of parts.
Therein lie several of the car’s advantages. “Any time you reduce the complexity of a system, you reduce the propensity for something to break,” says Earle. Beyond that, he adds, the method plays to one of 3D printing’s biggest advantages: mass customization. Eventually, he predicts, customers will be able to help design even the shape and size of their own car.
What’s more, Local Motors can greatly reduce the time to market. Where car development can often take 5 to 7 years, Rogers plans to release model updates up to 10 times per year, bringing transportation up to pace with software and phone releases. “It’s going to put car building in the hands of younger and more nimble people,” he says. “I think this is going to unleash an entire different wave of people who are engaged in hacking their car ecosystem.”
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