Local Motors 3D prints a car at the Detroit Motor Show

Local Motors is pioneering a 3D-printing technology in collaboration with Oak Ridge National Laboratory that squeezes carbon-reinforced ABS plastic through an ink-jet like nozzle so, bit-by-bit, an entire car chassis can be created. The carbon fiber gives the plastic a lot more strength.

Once printed, the body is milled and polished so it's smooth and then it's ready for the wheels, electrics and steering and motor to be attached. Local Motors is sourcing those from the Renault Twizy, an electric-powered city car produced by the French auto maker.

The process enables prototypes to be created much faster than with traditional fabrication technologies and is cheaper for small runs, Local Motors said.

The Arizona-based company hopes to begin commercial production of cars this year and is building micro-factories in Knoxville, Tennessee, and in National Harbor, which is near Washington, D.C.

The company's Strati concept took about 44 hours to be printed and consists of about 1,100 pounds of plastic, which costs about $5 per pound.

In a test ride at the Detroit Motor Show of a car printed before the show began, the Strati proved to have quick acceleration. The track was too small for the car to get up to its top speed of 44 miles per hour, but it certainly seemed capable of the task. The plastic body appeared sturdy and didn't show any obvious signs of flexing or weakness.

The car's battery has a range of between 40 miles and 60 miles depending on the driving conditions.

Before the cars hit the street, they will have to pass safety crash tests.

Martyn Williams covers mobile telecoms, Silicon Valley and general technology breaking news for The IDG News Service. Follow Martyn on Twitter at @martyn_williams. Martyn's e-mail address is martyn_williams@idg.com