Previewing 3D-Printed Cars at the 2015 Detroit Auto Show

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Local Motors has been making a splash at shows such as SEMA and Detroit by 3-D printing its Strati EV on a Cincinnati Inc. BAAM (Big Area Additive Manufacturing) 7-by-12-foot-bed 3-D printer right on the show floor. Downstairs at Detroit I got a ride in the first-gen Strati just as the company was announcing a mid-cycle refresh (revised headlamps, taillamps, windshield mounts, and the like). What are we, six months into the development of Gen 1? Welcome to the world of 3-D-printed cars: Tweak the design, hit send, print the face-lifted model.

The ride was EV-fun, as the carbon-fiber-reinforced ABS plastic body/chassis weighs just 1,100 pounds, and it gets its 16-hp electric drivetrain (and its suspension) from the tiny Renault Twizy electric quadricycle, so it sprints around as quickly and nimbly as you'd expect. With precious few body/chassis parts to be joined, it feels ultra-rigid. A 6.1-kW-hr battery provides a claimed 62-mile range and tops out at 50 mph. It's envisioned as a kit-car neighborhood electric vehicle and will sell for $18K-$30K.

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At its Detroit press conference, Local Motors announced it will open two microfactories, one in Knoxville, Tennessee, and one in National Harbor, outside Washington, D.C. These small operations will be set up to produce some 3,000 vehicles, tailored to local needs. For example, the one near D.C. might build small electric shuttle-type vehicles for a real estate developer. The Knoxville plant will reportedly produce a more mainstream four-seat all-weather vehicle that will be unveiled at the New York International Auto Show in April.

The technology for printing this carbon-fiber-reinforced ABS plastic was developed by Oak Ridge National Labs.

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Oak Ridge was also on hand during the press days, showing off its own 3-D-printed car. This one was conceived, designed, 3-D-printed, milled, painted, assembled, and driven in just six weeks. Yes, an entire drivable car was created from thin air in six weeks.

The team decided on a Cobra in large part because the computer math for its iconic surface is available in the public domain and because parts such as the windshields, lamps, mirrors, and so forth are all easily sourced. They also did it in part to celebrate the 50th anniversary of Shelby's manufacturer championship win. This demonstration project has the full blessing of Shelby American. A rolling chassis was quickly designed to accept a Mustang front suspension and a Cadillac ATS rear suspension (metal mounting points can be easily encapsulated in the 3-D-printed material) and to house a front-mounted A123 15-kW-hr electric battery, a rear-mounted TM4 Inc. 134-hp drive motor, and GKN single-speed transaxle. Packaging this hardware required the bodywork to be widened slightly, which was easily accomplished using the computer model. The design phase lasted only a week.

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The body was formed in three sections, using a smaller "printer head" than the one printing the Strati (2/10ths of an inch versus 3/10ths), with some executed in a single spiral motion, creating the body section vertically, resulting in a Cobra-shaped tube that was later trimmed. Printing the body and chassis took another week, and it weighed 450 pounds -- not bad at $5/pound. The result was sanded smooth and gel-coated to a perfect class-A finish, and the oak-leaf shape on the hood is clearcoated to show off the layers of plastic.

The finished product was driven six weeks after the project started. Weighing 1,550 pounds total, it's said to be capable of accelerating to 60 mph in 5.0 seconds. You can't buy this or any other ORNL vehicles. The point of this exercise was to demonstrate the speedy development cycle allowed by the tech. The real payoff will be with rapid prototyping. A mold for a fiberglass hood was sitting nearby. It had been printed, milled, polished, and gel-coated in two days. Creating such a tool by conventional means is a weeks-long, $100,000-plus undertaking. This one cost a few thousand. Now that's one heck of an enabling technology.

Don't miss our comprehensive2015 Detroit Auto Show coverage RIGHT HERE, with plenty of photos from the auto show floor.

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