Additive Manufacturing

3D printed automotive prototypes

Automakers, parts manufacturers and racing teams all stand to benefit from the revolution in additive manufacturing (AM). The automotive market is one of the world’s biggest manufacturing marketplaces. In 2016 alone, there were 88.1 million passenger and light commercial vehicles sold, up 4.8 percent year-over-year.

3D printed automotive prototypes

Visuals of clay being carefully removed from a traditional automotive model are gradually being replaced by CAD files converted into three-dimensional prototypes. AM processes like stereolithography (SLA) and fused deposition modeling (FDM) produce visual prototypes of individual parts or entire concept cars.

In 1986, Ford Motor Company purchased SLA 3, the third 3D printer of its kind ever produced. Since then, the automaker has manufactured more than half-a-million parts and prototypes using AM processes, saving billions of dollars in the process. Reduced lead times dramatically accelerate new model development, and some prototypes are produced for 1/100th of the cost incurred using traditional methods.

Whether it is dashboards or entire cabins for one-of-a-kind concept cars, automakers now embrace additive manufacturing as never before. Post-processing often includes hand finishing, priming and painting, resulting in a visually pleasing concept car.

With AM, designs with complex geometries distribute build material only where it is strategically required to meet automotive performance standards. Often, 3D-printed parts weigh less than half what their cast or machined counterparts weigh. The design process is dramatically attenuated with on-the-fly alterations a mere mouse click away.

Early adopters in the automotive industry used one-of-a-kind printed prototypes for wind-tunnel testing. AM processes offer cost-effective alternatives to the traditional manufacturing of car components, especially complex and unique parts.

Automotive engineers and designers have long relied on thermoplastics to simultaneously save money, reduce weight, enhance aesthetics and deliver the required performance. FDM uses feedstocks like ABS, PC-ABS and Ultem in the production of automobile components, while electron beam melting (EBM) uses titanium, cobalt chrome and stainless steel metal powders.

At the Oak Ridge National Laboratory (ORNL), BAAM is known as an oversized 3D printing process rather than a dramatic sound. BAAM is the acronym for Big Area Additive Manufacturing, a process that makes 3D-printed concept cars even more of a possibility. With feed rates approaching 80 lb/hr,and print sizes as large as 12-ft x 7.5-ft x 6-ft, these big machines take 3D printing to a new level. The BAAM system has been used to print automobiles and a house from acrylonitrile butadiene styrene (ABS) filament infused with carbon fiber.

ORNL has an even larger machine under development that is known by the acronym WHAM, for Wide and High Additive Manufacturing. It is essentially an FDM extruder fitted to a vertical CNC machine. Parts as large as 46-ft long, 23-ft wide and 10-ft high are possible. A projected build rate of 1,000-lb/hr is 25 times that of the BAAM process.

Automakers seek to further exploit AM’s capacity for rapid prototyping, weight reduction, simplified assembly and streamlined supply chains. Using SLS and selective laser melting (SLM), it is now possible to print end-use parts like custom spoilers, bumpers, windbreakers and other car components. SLM is employed to fabricate exhausts and emissions systems from heat-resistant aluminum alloys. Pumps and valves are printed using sophisticated electron beam melting (EBM) technology.

AM processes are gradually yet inexorably moving the automotive industry from customized components to mainstream car production.

3D printed spare car parts

3D-printed spare car parts streamline supply chains. Parts printed on-demand reduce or eliminate inventory. Printing automotive parts on-demand potentially address regulatory requirements regarding how long automakers must keep spare parts on hand. A significant reduction in automotive parts inventories maintained for compliance could save many millions of dollars in production and storage costs.

Short-run, automotive components with complex internal structures are often produced more economically using AM processes rather than traditional investment casting, injection molding or CNC machining. Complex components including many parts that previously required time-consuming assembly can now be replaced by single or two-part assemblies. Many inherent qualities of additive manufacturing make it ideal for the localized production of spare car parts.

AM is already making inroads in the production of detailed engine components with complex geometries that reduce the overall number of engine parts. It is inevitable that ever-larger AM systems with greater production capacities will stimulate interest in the 3D printing of larger and larger automotive components. AM processes like SLS and SLA produce dashboards and seat frames from thermoplastic polymers. SLS systems can also use aluminum and other metal powders to fabricate body panels and doors. It is even possible to use SLM and PolyJet technologies to produce tires and hubcaps.

Looking to the future: Manufacturing 3D printed cars

Automotive enterprises of virtually any size can innovate and compete in a world of AM processes. In 2014, the Strati, a neighborhood electric car, and the Urbee, a hybrid car, vied for the title of the first 3D-printed car.

The prototype Urbee is a two-seat vehicle with 3D-printed bodywork and windows. The Urbee-2 is a second-generation prototype that its developers promote as the “world’s greenest car.” To demonstrate its practicality and fuel-efficiency, the Urbee-2 completed a cross-country trip consuming just 10 gallons of biofuel, setting a record in the process. The 2015 journey took just two days to complete with two people and a dog on-board.

Local Motors has designed innovative vehicles and other products since 2008. Its 3D-printed car, the Strati, makes extensive use of additive manufacturing. A Strati was printed in just 44 hours at the 2014 International Manufacturing Technology Show in Chicago, Illinois. A high-speed video of the printing of the Strati may provide a glimpse at the future of this new kind of automotive manufacturing. BAAM’s fused deposition modeling technology achieved the feat, using ABS polymer infused with carbon fiber as the build material. Milling and finishing added three days to the process. Everything on the Strati, excluding mechanical components, is 3D-printed. The company envisions a future of online ordering of customized vehicles produced in energy-efficient micro-factories.

Growing interest in personalized bespoke cars matches perfectly with the development of advanced AM processes for fabricating metal, thermoplastic and composite automotive components.