Recently, a startup Italian car company called XEV launched a two-seat electric vehicle. When it goes into production at a plant in Jiangsu, China, next month, the LXEV will become the world’s first mass-produced printed car.
However, that low-volume niche vehicle is the exception rather than the rule. Most cars and trucks still rely on thousands of metal and plastic parts that are produced using traditional casting, forging, injection molding, machining and stamping processes.
While that scenario is not likely to change any time soon, production-ready printed automotive parts are slowly entering the market. In fact, they can now be found on high-end performance vehicles such as the BMW i8 Roadster, the Bugatti Chiron, the Ford Shelby Mustang GT500 and the Lamborghini Urus.
BMW claims that it has already produced a million parts through additive manufacturing. Last year alone, it made more than 200,000 components—a 42 percent increase from 2017. Those parts are used for a wide variety of applications, including production tools, fixtures and jigs.
Ford Motor Co., which purchased the third 3D printer ever made in 1988, now has more than 90 machines globally producing parts and tools. Ford has also invested in several additive manufacturing equipment vendors, such as Carbon and Desktop Metal Inc.
On the factory floor, Ford engineers and operators are harnessing the technology to identify ways to save the company time and money. For instance, at some plants, they’re printing replacement parts to keep assembly lines running instead of waiting for wearable items that can take weeks to be fabricated with traditional techniques.
Additive manufacturing “prints” solid objects from a digital file by depositing one layer of material on top of another, rather than starting with a solid piece of material that is cut, molded or shaped. It allows companies to more easily manufacture complex shapes and structures that have traditionally been difficult to make with subtractive manufacturing methods.
With additive manufacturing, automotive engineers can go from design to finished product in a matter of hours rather than weeks or months, which helps streamline new product development and reduce time to market. There’s also less waste, which results in shorter setup times and lower material costs.
Plastic parts are typically made using ultraviolet, infrared or visible light in conjunction with laser or heat energy. Metal parts are produced with laser-based or electron beam-based printers that often use metal powders for raw material; the laser or electron beam fuses together the powder.
With additive manufacturing, multicomponent automotive parts that previously required assembly can now be printed as a single object. Engineers can consolidate multiple assemblies into one part, eliminating time and assembly costs.
“Motorsports and some luxury automakers have been rather fast in adopting additive manufacturing for part production,” says Davide Sher, senior analyst for Europe at SmarTech Markets Publishing. “However, these are very small batches of parts or even single parts, which is more similar to demand in the aerospace and medical device segments that have widely adopted additive manufacturing technology.
“The mass-market automotive industry has much tighter cost constraints than those industries,” notes Sher. “[Ironically], the automotive industry was one of the very first adopters of 3D printing technology for prototyping applications.”
“The big difference between automotive and medical applications is customization,” says Andrzej Nycz, an R&D engineer at Oak Ridge National Laboratory who specializes in additive manufacturing technology. “Most printed implants, such as replacement knee or hip joints, are custom made and cost is less important. On the other hand, the automotive industry typically requires millions of parts that share the same shapes and geometries. As a result, speed and cost are more critical.”
According to Nycz, the challenges in additive manufacturing have recently changed. “Five years ago, the focus was on creating complex geometries,” he points out. “Today, additive processes are required to be faster, larger and use an increased range of materials.”
“As the cost of additive manufacturing hardware and materials decreases, automotive companies are starting to find the technology to be cost-effective for some types of applications, such as small-sized parts and parts with complex geometries,” says Sher.
“Even more importantly, a new generation of high throughput metal and plastic planar technologies, along with materials such as aluminum and aluminum alloys, are expected to soon make larger batch part [printing] cost effective for production runs of up to 50,000 units,” Sher points out.
Lightweighting Drives Demand
Widespread interest in production-ready printed parts is being driven by numerous lightweighting challenges facing automakers and suppliers.
“Additive manufacturing adoption in the aviation industry has already demonstrated, without any doubt, that it is the only possible production technology that can effectively address lightweighting,” says Sher.
“In aerospace, costs are much less of an issue than in automotive,” notes Sher. “However, decreasing costs of 3D printing hardware, software and materials, along with increasing lightweighting requirements in light of electric mobility’s demand for increased range, are now making these technologies cost effective in automotive production as well.”
By harnessing digital optimization design software, engineers can push the geometry of parts. The tools make it possible to control where to apply more material and where to remove material entirely.
“This results in highly complex part geometry, such as lattices and trabecular structures, that cannot be manufactured by any traditional formative or subtractive means,” says Sher. “With additive manufacturing technology, it is actually cheaper to produce these more complex structures, since less material is required, than to produce standard parts via lengthy production processes.”
Packaging and positioning parts, such as brackets, have been a popular application for recent additive manufacturing efforts in the auto industry. Optimized brackets can hold seats, wiring harnesses and other components in place and reduce mass.
“Lightweighting is a perfect match for additive manufacturing,” says Avi Reichental, vice chairman of Techniplas, a Tier One supplier to BMW, Daimler, Fiat, Ford and other automakers. “It enables engineers to create more efficient, organic structures that provide the same performance as traditionally designed components, but weigh much less.”
For instance, by using additive manufacturing technology, engineers at General Motors recently produced a functionally optimized metal bracket that is used to attach vehicle seats to floors. They consolidated a boxy part consisting of eight components into one stainless steel piece that is 40 percent lighter and 20 percent stronger.
Ford engineers recently printed a plastic electric parking brake bracket that is 60 percent lighter than a stamped steel version.
The emergence of generative design software has made it easier for automotive engineers to address lightweighting challenges through additive manufacturing.
“Generative design mimics nature’s evolutionary approach to design,” says Sean Manzanares, senior manager of business strategy and market development at Autodesk Inc. “Engineers input design goals along with parameters such as materials, manufacturing methods and cost constraints.
“Unlike topology optimization, the software explores all the possible permutations of a solution, quickly generating design alternatives,” explains Manzanares. “It tests and learns from each iteration what works and what doesn’t. Generative design uses design constraints like weight, strength and manufacturing method entered by the engineer to generate a set of solutions that fit within those constraints.”
“You can use the software to create a design that is optimized for weight,” says Paul DiLaura, vice president of enterprise partnerships at Carbon. “That enables engineers to reduce mass while maximizing stiffness.”
Last year, Carbon unveiled a high-strength material for automotive applications. Epoxy-based EPX 82 has been validated by manufacturers such as Aptiv, Ford and Lamborghini. They’ve used the material to print brake brackets, delete plugs, fuel caps, HVAC lever arms, electrical connectors, electronic housings and many other types of automotive components.
Carbon’s equipment uses digital light synthesis technology to produce parts that have high-quality mechanical properties, resolution and surface finish. According to DiLaura, automotive components printed with this process are similar to plastic injection-molded parts, and have consistent and predictable mechanical proprieties.
“Different parts of a vehicle have different requirements for printed material properties,” says DiLaura. “We’ve focused on electrical and fluid connection systems where parts can be quite complex and difficult to produce with injection molding. There’s value in having unique designs that are possible with additive systems.”
In addition to plastic parts, automotive engineers are exploring new ways to mass-print metal components.
“Until now, metal 3D printing has been limited to aerospace and medical device applications,” adds Jonah Myerberg, chief technology officer at Desktop Metal. “The automotive industry hasn’t been able to justify the economics. But, more engineers are now starting to design for additive manufacturing, because they now have an ability to mass-produce printed parts.
“Today, most automakers outsource the production of high-volume small metal components,” says Myerberg. “In the near future, we expect them to demand that their suppliers produce more printed parts.”
To address that shift in production philosophy, Desktop Metal recently unveiled a printing system that delivers the speed, quality and cost-per-part needed to compete with traditional manufacturing processes.
“The Production System is more than four times faster than any binder jet competitor and offers a 100 times speed improvement over any laser-based system,” claims Myerberg. “It features 32,768 piezo inkjet nozzles that enable the broadest range of binder chemistries to print an array of metals, including low-alloy steels, titanium and tool steels, at a rate of 3 billion drops per second.
“The machine can print more than 60 kilograms of metal parts per hour,” explains Myerberg. “That translates into more than 100 metric tons per year, which is the equivalent of a stamping machine running millions of parts.
“Aluminum printing is something that we’re currently working on,” says Myerberg. “We expect to have something commercially available within the next three years.”
“The most highly sought after materials for metal printing today are steels such as 17-4 stainless and 4140 chrome-molybdenum,” notes Myerberg. “They are compatible with materials already being used in the auto industry that engineers have worked with in the past.
“Parts printed with these materials are weldable with existing materials and can be attached with mechanical fasteners,” Myerberg points out. “That enables engineers to drop these types of printed parts right into an existing assembly. However, any stressed component that is printed must have the same performance characteristics as a part that is traditionally cast or stamped.”
Beyond Brackets
So far, most production-ready additive manufacturing applications in the auto industry have involved basic parts, such as metal brackets or plastic clips. The next big step is to mass-produce other types of nonstructural components.
“Additive manufacturing has given us the tools to design for function,” says Harold Sears, technical leader for additive manufacturing at Ford Motor Co. “It opens up a lot of design freedoms. That enables us to consider using organic-looking shapes that would be impossible to make any other way.
“Parts can also be optimized for minimum material usage and maximum lightweighting,” explains Sears. “That’s important as we move to more electric vehicle platforms where weight is critical.
“In the last few years, we’ve seen improved additive material properties and faster speeds of printing machines,” adds Sears. “The challenge today is to move beyond simple applications, such as printing little brackets.
“Until now, we’ve been proving that the technology is capable of producing parts that meet tight specifications and delivering them consistently,” explains Sears. “We’re now starting to apply the technology to production-ready parts used on niche vehicles.”
Sears and his colleagues at Ford’s Advanced Manufacturing Center are busy experimenting with more than 20 printers from suppliers such as Carbon, Desktop Metal, EOS, ExOne, HP, Stratasys and Voxeljet. That variety enables the engineers to examine new ways to build parts from a wide range of metal and plastic materials.
“One application currently under development has the potential to save [us] more than $2 million,” claims Sears. “As [the technology] becomes more affordable, [printed] parts will become more prevalent. However, because large size presents numerous challenges, most efforts will focus on smaller, more intricate parts.”
Brackets, clips and other basic components are inexpensive to make with traditional molding and stamping processes. Instead, the focus will be on more complex, high-value auto parts.
“There’s a great deal of interest in under-the-hood, high-temperature plastic components, such as ducts and manifolds made from nylon,” says Reichental. “Other potential applications include power train components, brake calipers and shock absorbers.
“As the automotive industry shifts toward more autonomous vehicles, the purpose and functionality of cabins will also change,” adds Reichental. “There will be growing demand for printed parts that provide customization. Nonstructural interior component applications for additive manufacturing include cupholders, dashboard inserts, door panels and storage compartments.”
Techniplas engineers recently developed a concept vehicle that demonstrates several advanced capabilities, including a trailing suspension arm boasting a 48 percent weight reduction and a seat back that shows how additive manufacturing can reduce assembly time, part count, material usage and overall cost without any performance degradation.
The concept vehicle highlights the expanding capabilities of the company’s Techniplas Prime e-manufacturing platform. It leverages the company’s core engineering expertise and manufacturing facilities, together with dozens of its qualified manufacturing partners such as Nexa3D, NXT Factory and ParaMatters.
“Prime is the industry’s first [design platform] to provide online lightweighting solutions, additive manufacturing options with instant pricing quotations, and localized serial manufacturing for the auto industry,” claims Reichental.
Techniplas also recently unveiled a new steering wheel concept that incorporates its proprietary cognitive lighting technology with 3D-printed electronics. Using a Nano Dimension DragonFly printer, Techniplas engineers directly printed conductive paths into a concept wheel in a single step.
“Our cognitive steering wheel concept is just the beginning of a journey that we believe can shape the way electronics, sensors, antennas and smart illuminations are designed and manufactured for the connected car era,” says Reichental. “The combination of smart lighting with additive electronics can shape and transform the future of mobility, enabling the creation of customized and short-run functional electronics, such as conductive geometries, molded connected devices, printed circuit boards and other devices.”
“A complete [high-volume] vehicle will probably not be manufactured by a 3D printer any time soon, but the number and size of [printed] parts will increase significantly,” notes Martin Goede, head of technology planning and development at Volkswagen. “Our goal is to integrate printed structural parts into the next generation of vehicles as quickly as possible. In the long term, we expect a continuous increase in unit numbers, part sizes and technical requirements, right up to soccer ball-size parts of over 100,000 units per year.”
Goede believes that the first structural components for mass-produced vehicles could be printed in two to three years. “But, not all of the 6,000 to 8,000 components used in a vehicle would come from a printer,” he explains. “In particular, large, less complex parts like the hood will still be able to be produced faster and more cost efficiently by using traditional processes.”
According to Goede, Sears and other experts, volume requirements in the automotive industry have hindered the widespread use of additive manufacturing for production-ready parts.
“When you have to make 200,000 to 300,000 parts a years to support just one vehicle platform, the technology is not yet economically viable,” says Sears. “But, the future is exciting.
“Within the next five years, we’re going to be seeing some new technologies and processes that will enable us to print parts in high volumes,” predicts Sears. “It will be a game changer in the auto industry, because machines will be able to support the next vehicle program that comes along. Instead of traditional retooling, it will just be a matter of loading different CAD files and qualifying the new part. The machines will continue to provide return on investment.
“Power train and chassis applications will drive a lot of the metal additive manufacturing technologies,” notes Sears. “Interior and trim applications will continue to push the envelope on the plastics side.
“However, automation will be critical to making additive manufacturing work in high-volume applications,” Sears points out. “It will help address problems with variance and inconsistent part builds. Automation will add stability and enable us to transform 3D printing from a batch process to a continuous process that will work much better in a volume production setting.”
Controlling the quality of production-ready printed parts is another hurdle facing automotive engineers today. Indeed, one of the biggest benefits of additive manufacturing—the uniqueness of every component that comes off a 3D printer—is a potential roadblock, because it means a close analysis of one part is no guarantee that the next part will be acceptable.
Before printed parts are used in critical areas of an automobile, engineers must perform rigorous quality control on every part that’s produced.
“We have been doing a lot of tensile testing and impact testing on printed parts, looking at the performance of the materials,” says Mark Noakes, senior R&D engineer at ORNL. “For instance, once we print something, how do we guarantee that it’s an acceptable component?”
“We wrongly assume that what you print will be identical to what was designed,” adds Suresh Babu, a materials engineer at ORNL. “Printing involves a very complex temperature profile for the material due to multiple heating, melting and cooling events that are all interconnected and inherently dependent on one another.
“The challenge is that this complex process governs the underlying physics of the material—things such as porosity, defect structure and nonuniform microstructures—and creates uncertainty over how the part will ultimately perform,” notes Babu. “This uncertainty means [automakers] must conduct exhaustive testing and inspection. That drives up cost and can limit the real-world usefulness of additive manufacturing.”
When the geometry of a printed part changes, Babu says the entire certification process must be reperformed for the new geometry. That’s why analysis on the strength of materials has been a major focus of ORNL’s recent R&D activity.
“Small metal brackets used for seats and other automotive components are just the beginning,” claims Desktop Metal’s Myerberg. “Stressed and moving components, such as engine valves and transmission gears, are parts that can benefit from additive manufacturing. Metal printing enables engineers to address lightweighting issues and build internal features that help with cooling.
“Power train is where a lot of small steel components live,” says Myerberg. “We’re seeing a lot of applications between the differential and the wheels. Engineers are also consolidating parts that are bolted together.
“However, serviceability is a major concern to automakers,” Myerberg points out. “Many engineers are trying to understand the implications of what happens when you replace multiple parts with a single printed component. For instance, will repair costs increase or decrease?
“Ultimately, engineers would love to be able to print an entire chassis or a body in white,” says Myerberg. “That is still at least five to 10 years away, however, because of current limitations on build envelopes.
“But, within the next decade, the automotive industry will be completely transformed in the way that it makes metal parts,” predicts Myerberg. “The heavy, hard tooling that’s been used for decades will become an artifact. Tools will be soft and live in servers. Parts are going to be maintained in real time and design improvements will happen much faster.”
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