Local Motors showed off its 3-D printed car, named the Strati, during a luncheon this week at the Reagan International Building in Washington, D.C. Just about the entire body of the vehicle was created on a 3-D printer with about 60 components added on later, such as wheels, engine and seats. The windshield was also custom made for the car.
“We converted the surface model of the windshield into a solid model and exported it into Autodesk 123D Make,” explained Nick Bauer, a mechanical engineer with Local Motors who was responsible for creating the windshield. “I cut out the 2-D structure on the waterjet and assembled the plywood cutouts into a 3-D mold pattern. After the pattern was made, expanding foam was poured into it. It was then trimmed to the pattern and topped with three layers of fiberglass chop matt.
“The chop matt was trimmed and imperfections were filled in with resin or body filler,” he added. “The material was then trimmed and sanded smooth and topped with felt. We then obtained 3/8-inch thick clear cast acrylic and heated the material in a thermoform oven at 400 degrees for about one minute. We then draped the pliable acrylic over the mold and used ten guys or so to hold the sides down until cool. The material was then trimmed and polished.”
The Strati body was built on a Big Area Additive Manufacturing (BAAM) machine at Cincinnati Inc., in cooperation with Oak Ridge National Laboratory.
“The BAAM machine can be used for actual production,” says Andrew Jamison, CEO of Cincinnati Inc. “The deposition rate of 40 pounds per hour of carbon reinforced ABS plastic and the large size mean that large parts, like a car, can be produced using additive technology.”
The car was created in three stages. First, the body was built on the 3-D printer, taking 44 hours.
“About a month ago, it would have taken 140 hours,” noted Kurtis Hodge, a microfactory economist for Local Motors. “We worked with the technology to get it down to 44 hours. We’d like to get it down to taking about a day.”
Next, the company used the milling stage to smooth out the surfaces of the vehicle’s body and to clean up the aesthetics.
The final touches, such as engine, wheels and seats were added through the rapid assembly stage.
“We got it down to about 60 parts from 20,000 in a traditional car,” Hodge pointed out.
“Nobody has really made a vehicle this way before,” he added
“Bringing a new vehicle to the industry is what I am all about,” said John Rogers Jr., CEO of Local Motors, when the car rolled out during the luncheon. “ … I was on a hunt for 18 months to radically reduce the parts in a car. … Let’s put the patents to the side … and make the competitive advantage speed to market.”
He concluded by inviting attendees to take photos with the vehicle, noting, “The car is a piece of history and we expect it to be in your garage soon.”
He hopes to bring the car to market within 12 months.