The first extruded Cobra

A Cobra in the making using rapid 3D printing.

TWO 3D-printed cars showed the very different face of car manufacturing at last week’s ­Detroit Auto Show.

Local Motors printed and ­assembled an entire vehicle on the event’s show floor, while the Oak Ridge National Laboratory (ORNL) showed a vintage 1965 Shelby Cobra they had 3D-printed in six weeks.

Local Motors called their 3D car the Strati, saying it was the first in a line of 3D-printed cars from
Local Motors. The design was chosen in May 2014 from more than 200 submitted to Local Motors by the company’s online co-creation community after launching a call for entries.

The winning design was submitted by Michele Anoè, who was awarded a cash prize plus the opportunity to see his design brought to life.

“Since launching in 2007, we have continuously disrupted the way vehicles are designed, built, and sold,” said Local Motors ­Co-founder and CEO John B. Rogers Jr. “We paired ­micro-manufacturing with co-creation to bring vehicles to market at unprecedented speed.

This Shelbey Cobra was, believe it or not, 3D printed.

“We proved that an online community of innovators can change the way vehicles go from designed to driven. We pioneered the concept of using direct digital manufacturing (DDM) to 3D-print cars. I am proud to have the world’s first 3D-printed car be a part of our already impressive portfolio of vehicles.”

It’s a “Three-Phase Process: Print, Refine, Finish”.

The Cobra printed by ORNL followed the same steps.

“You can print out a working vehicle in a matter of days or weeks,” says Lonnie Love, leader of ORNL’s Manufacturing Systems Research group in their media handout.

Thanks to 228 kg of very light 3D-printed parts containing 20% carbon fibre, the Cobra weighs only 635 kg.

The chassis in 3D layers.

The car was built at the U.S. Department of Energy’s Manufacturing Demonstration Facility at ORNL using the Big Area Additive Manufacturing (BAAM) machine developed by ORNL and Cincinnati Incorporated. ORNL says that this device can print objects larger than a cubic metre in volume 500 to 1 000 times faster than current industrial additive printers.

ORNL said the 3D printing part of the design and finishing process took 36 hours, of which a day was spent printing the Cobra’s parts, eight hours went into printing the tooling components, and four into machining the bodywork to ready it for paint.

Love said the 3D-printed Shelby dispenses with the current design process of drawings, CAD renderings, scale clay models, concepts, and prototypes. Instead designers can go straight from CAD to working parts vehicle that can be assembled in a very short time in a rolling laboratory to test new automotive technology.