Plastic Parts, Perspectives, and 3D Printed Cars

No, Thomas Edison did not discover that electricity could travel in a vacuum. Local Motors did not build the world's first 3D printed car either. Yes, there's been plenty of press about the Arizona automaker's achievement at the International Manufacturing Technology Show (IMTS) in Chicago last week. Have you been following the stories about the electric vehicle (EV) that Local Motors 3D-printed right on the tradeshow floor?

Industry Week cited the "sheer buzz" when the Strati (which means "layers" in Italian) drove away. Manufacturing.net was less impressed by how the direct digital manufacturing (DDM) process moved "ever so slowly", but still gave the 3D-printed EV the number 2 spot in its Top 10 from IMTS 2014 article. Apparently, robotic arms and graduate projects were of greater interest to the website's editors.

What Did Local Motors Really Do?

So what did Local Motors achieve (if anything), and why does it matter now that the 114,147 visitors to IMTS 2014 have all gone home? To be precise, the Arizona automaker assembled the world's first fully-electric car using 3D printed auto parts. No, local Motors didn't 3D-print every single part. Mechanical components like the battery, motor, wiring, and suspension were sourced from a variety of suppliers.

The Strati required assembly, too. Production was never as simple as the single push of a button, no matter what overly enthusiastic observers might say. Yet the Strati is important in other ways. For example, the auto-body design process was internationally competitive, the material science and advanced manufacturing technologies were collaborative, and the 3D printing process took just 44 hours. Moreover, unlike a conventional car, the Strati required the production of only 40 parts.

Advancements in Additive Manufacturing

Although the car was produced in Chicago, the concept came from Italy's Michele Anoé, winner of the Local Motors 3D Printed Car Design Challenge. Oak Ridge National Laboratory (ORNL), a pioneer in advanced materials research, and Cincinnati Incorporated, maker of large-scale manufacturing systems, then leveraged a recent partnership that's designed to accelerate development of 3D printing systems for large plastic parts.

For its part, Local Motors used a Big Area Additive Manufacturing Machine (BAAM) to produce auto parts made from carbon-fiber reinforced plastic pellets. Chosen because of its excellent strength-to-weight ratio and high stiffness, this compound from Sabic includes acrylonitrile butadiene styrene (ABS), the same plastic that's used in Legos. Reportedly, the ratio is 20% carbon fiber and 80% ABS resin.

Still Not Impressed?

If you're more interested in the world's first 3D printed car, then the Strati won't rev your engines. In 2010, engineers from Winnipeg and Minneapolis built the Urbee Hybrid, an electric/liquid fuel (gasoline or ethanol) vehicle with a highway fuel economy of 200 mpg (1.2L/100 km). Stratys, which created all of the automobile's exterior, used fused deposition modeling (FDM) to 3D-print thermoplastic auto parts.

Consider what's changed in just four years, however. Although there are important differences (such as the powerplant), between these two 3D printed vehicles, the Urbee took 2,500 hours to produce. The bumper alone, which is made in two pieces, required a total of 300 hours. Although small printing jobs for the Urbee can be completed overnight, larger parts can take several days.

As engineers, do you think that Local Motors accomplished something substantive at IMTS 2014? Or is the world's first 3D printed electric car just more hype about additive manufacturing? I hope you'll share your insights and comment on this blog entry.

About the Author: Doug Sharpe is the President of Elasto Proxy, Inc. (Boisbriand, Quebec, Canada), supplier of sealing solutions and custom-fabricated rubber and plastic parts to a variety of industries, including automotive, mobile specialty vehicles, and mass transit. Visit Elasto Proxy at IHS GlobalSpec's Automotive Event on 9/24. Register now at bit.ly/ATT2014