Large-scale additive manufacturing made it possible to 3-D print CFRP parts for the self-driving Olli mini-bus. Photo credit: Local Motors

As the company explains, passengers can interact conversationally with Olli while traveling from point A to point B and ask questions about how the vehicle works, where they are going and why Olli is making specific driving decisions. Passengers can also ask for recommendations on places to go.

Local Motors says that up to a third of the vehicle was 3-D printed, including the shape that was used to create the mold for Olli. The CFRP used for the vehicle is 80 percent acrylonitrile butadiene styrene (ABS) and 20 percent chopped carbon fiber. In total, Olli weighs 3,300 pounds.

According to Charles Hill, an advanced materials engineer at Local Motors, the company turned to Oak Ridge National Laboratory and Cincinnati Incorporated’s Big Area Additive Manufacturing (BAAM) technology to create molds for thermal forming of ABS sheets for the interior panels of the bus. He says Local Motors produced 15 molds in about five days for two pilot program vehicles.

“That was one of the keys to this rapid development – to utilize this large-scale additive process to build the molds for vacuum thermal forming,” says Hill. He says that Olli features about 11 individual parts, including fenders, wheel wells, the front and rear panels, and interior kick panels, which were produced directly by large-scale 3-D printing using the same materials that the company used to make the 15 molds. Local Motors used the same process to make parts for the Strati, the world’s first 3-D printed vehicle, as well as its LM3D Swim, the world’s first 3-D printed car series.

Hill adds that Local Motors also used “more conventional composite parts” for about 10 body panels for the bus’s outside corners, roof panel and side panels. The continuous carbon fiber prepreg materials for those panels, which utilized an epoxy resin, were supplied by Roding Automobile in Germany.

Hill says the next step for Local Motors is to reduce the number of parts for the self-driving mini-bus and significantly reduce the assembly time required for future vehicles.

We’re working right now … to further develop the large-scale 3-D printing, and we’re investigating a number of new materials to increase the mechanical properties of the 3-D printed parts,” says Hill. “In the future, we look to this process to be able to build more of the vehicle directly with 3-D printing.”