At the 2015 Detroit motor show, we talked to Lonnie Love, group leader for automation, robotics and manufacturing at the Oak Ridge National Laboratory, about not only his team’s 3D printed replica of the Shelby Cobra, but also about what impact 3D printing may have on the world of automobile manufacture.
While the 3D printed Cobra (below) is an impressive piece of kit, it’s only meant as a rolling showcase for "where advanced materials, lightweight composites, new manufacturing processes are going”.
Unlike traditional car manufacture, where every metal or carbonfibre component requires an expensive tool or mould in order to be created, with printed cars "you go straight from your CAD model to [the printed] the final part”. Due to the elimination of tooling costs, Love believes that for producers "looking at thousands of cars or maybe tens of thousands of cars a year, [3D printing] may make sense”.
The two 3D printed cars on display in Detroit limit their printed components to the body and chassis, but the Oak Ridge team is also working on 3D printed internal combustion engines and other components.
Another upside is that 3D printing could help to make more efficient use of the space available within a car. For instance, battery packs could easily be designed and printed to fill up any unusually sized cavities available, instead of being restricted large rectangular blocks that rob storage space.
3D printing cars may also benefit from enhanced safety. According to Love: “Right now [cars] have crash tubes that are integrated into the structure, they’re directionally dependent and assume that will be crushed in a certain direction, and if they’re hit off angle they don’t work as well. With [3D printed cars] we could create an organic, lattice-type structure inside that can absorb energy from any direction”.
As for how highly customised bodies and designs may affect the crashworthiness of printed vehicles, Love admitted that “that's an unanswered question and one we have to answer”.
He suggested a scenario where a manufacturer would design a chassis, complete with airbags, restraints and so forth, that would then be tested and certified, and to which customers could design their own bodies and modifications. To keep the car legal, any changes would have to fall within certain boundaries for weight, deceleration and aerodynamics.
To keep weight down and ensure a strong structure, both Oak Ridge’s Cobra replica and the Local Motors Strati, feature a chassis and body printed from carbonfibre-reinforced ABS plastic.
In order to make the economic equation, as well as pricing, more attractive, Loves says that Oak Ridge is also working with approximately 170 companies to reduce the cost of carbonfibre from between US$110 to US$180 a kilogram to closer to US$10 per kilo.
Even before all these improvements come online, though, Local Motors is planning to go to market with a customisable printed car, similar to the Strati (top), that's produced in a micro-factories turning out hundreds to thousands of kit unique cars per year.