Five years ago, Detroit auto show crowds scratched their heads over a car whose body, frame and interior emerged fully formed at the show from computer printers that laid down layers of carbon-fiber infused plastic to form the three-dimensional components.
The 3D printing of auto parts, demonstrated then by a small company called Local Motors, has accelerated from auto show curiosity to manufacturing necessity in just a few short years.
This year, printed parts logged 80,000 miles on Chevrolet's Corvette, IndyCar, NASCAR and Silverado race teams, while providing prototype duty on production vehicles like the Ford Mustang GT500.
With its hand-made cars and focus on immediate results, the racing industry is the current focus of 3D-printed parts, but manufacturers don't rule them out for production-line vehicles.
"We're on a journey of identifying opportunities across a number of areas including motorsports, product development and future production vehicles," said Ali Shabbir, General Motors Co.'s chief of additive design and manufacturing product applications. "Racing continues to be an excellent proving ground for new concepts and technologies leading toward production."
Leading the way is the mid-engine Corvette C8.R race car which bristled with 75 printed parts as it pounded through grueling endurance races to its first IMSA Weathertech Sportscar GT title this year.
Those parts included such essentials as the oil tank and oil cap, parts of the driver cooling-system, power-steering pump bracket and headlight assemblies. Fifty of the parts were made in-house by GM and survived some of the world's most punishing tracks including the washboard-rough Sebring Raceway in Florida.
The 3D printing process starts with a three-dimensional digital blueprint of a part that is downloaded to a printer. A nozzle on the machine lays down successive layers of plastic, metal or ceramic until a perfect physical representation is created.
The manufacturing process has become a mainstay of educational art programs with classes on how to make printed jewelry and decorative objects for the home. On a much larger scale, the technology has become essential to automakers as they seek to shrink production cycles.
Before they become rolling sheet metal, modern cars are developed with extensive computer modeling. Printed parts help to quickly assemble them into prototype cars for wind-tunnel testing and other development needs.
"Right now, we see large benefits in the pre-production space," said GM's Shabbir. "3D printing has the benefit of speed and quick iteration. With 3D prototypes, teams can rapidly check the viability of different versions of the same part, which can save considerable time during the development phase."
Ford showed off its pre-production assets — including supercomputers, printer and wind tunnels — to the news media last year ahead of the introduction of its 760-horsepower GT500 muscle car.
Crafted at Ford's Advanced Manufacturing Center in Redford, the printed prototype parts for the GT500 were fitted to the front end of a standard Mustang GT for testing at Ford's wind tunnel in Allen Park. The printed parts also did duty at the state-of-the-art Windshear wind tunnel in North Carolina that's used by racing teams.
"We did over 300 simulations in the virtual world, then we 3D-printed car parts and took it in the wind tunnel," Mustang GT500 aerodynamic engineer Matt Titus told The Detroit News.
The Team Penske racing team partnered in 2017 with Stratasys, a 3D printing solutions company, for tooling and engineering prototypes. Penske now uses printed components on its actual IndyCar racers. For example, the V-6 exhaust system was printed to eliminate failure points in traditional manufactured components while increasing design freedom and reducing cost.
NASCAR, too, is a hotbed for development. Chevy switched to the Camaro ZL1 1LE for this year's Cup Series, replacing the ZL1. The body of the new car underwent extensive wind-tunnel testing using over 500 printed prototype parts. On-track, the Camaro uses a printed gear-cooling duct, which logged 18,500 miles of competition in 27 races.
Printed parts even go off-road racing. The Chevy Silverado off-road race truck has in-house printer-generated components including a rear shock absorber shield for protection over rocky desert terrain.
Don't expect to see a car on a showroom floor anytime soon like the one with a body, frame and interior printed at the Detroit auto show. Individual components are a different story.
"GM's 3D printing capability speeds up our learning cycles," said Jim Campbell, chief of GM's U.S. Motorsports, "and, in turn, these racetrack experiences help our additive manufacturing team move one step closer to using 3D printed parts in production vehicles."
