Imagine the look on Henry Ford’s face if he walked into one of his factories today. Now try imagining his reaction if he toured the 3D-printing area. After peeking into the build chambers and seeing the products that emerge from them, the old mechanic would undoubtedly approve. He would also approve of Dr. Ellen Lee’s work at Ford Motor Co.’s research lab in Dearborn, Mich., where she and her team are continually searching for novel ways to utilize additive manufacturing at the 119-year-old automaker.
“Our intent is to use additive technology in all its many forms wherever it can create value for the company,” Lee said. “That currently includes prototyping, tooling, and other traditional AM uses, but what our research team is focused on is how we can use it for volume-production applications.”
Lee serves as the technical leader for Ford’s Additive Manufacturing Research team. She’s done so since 2015, building on her past positions as a technical specialist in plastics research and then team lead for that group. In all, Lee has spent 24 years with the automaker. She’s a graduate of Northwestern University’s bachelor’s program in chemical engineering, then earned her doctorate in the same subject at the University of California, Berkeley. She also was an adjunct professor at Wayne State University in Detroit, where she taught a graduate-level course in polymer solutions.
Simply put, Lee knows plastics. A quick review of her curriculum vitae will tell you she also knows nanomaterials, fiber-reinforced composites, supercritical fluid polymer processing, and more fundamental aspects such as “single-chain polymer dynamics in steady-state flow conditions.” And now, thanks to her involvement in all things additive, Lee is becoming quite knowledgeable on metals as well.
“Soon after my first introduction to additive manufacturing, I saw a big opportunity to expand its potential use cases,” said Lee. “I started learning as much as possible about the technology and eventually launched a research program focused on polymer AM development, which grew to include metals.”
That introduction came care of Harold Sears, Ford’s technical leader for additive manufacturing technologies at the company’s Advanced Manufacturing Center in Redford, Mich., one of five facilities worldwide at which Ford builds AM parts. Knowing of Lee’s extensive experience with polymers, along with some projects she’d led on material sustainability, Sears asked her for help finding ways to reduce, recycle, and reprocess the large amounts of waste powder he and his team were generating in what was then a prototyping-only facility.
Lee was intrigued by the challenge, and the more she learned about AM, the more she wanted to learn. She soon found herself in charge of a dedicated research program at Ford, where she and her team develop AM strategies and technical roadmaps for materials, as well as finding applications that will create value for the automaker. And, yes, they’ve discovered innovative ways to utilize spent powder more effectively.
“Our responsibility is to support the company with deep expertise on the various AM technologies used at Ford,” Lee said. “If the production area has questions that require a higher level of understanding, we’re here to help. Similarly, if a technology emerges that might benefit the enterprise in some way, we’ll investigate it, identify materials and processes that might require additional development work, and see if it makes sense to invest in further research. We have a long-term, far-reaching focus, one that extends out over the next decade or longer.”
During her time as technical team lead and before, Lee has also discovered that AM has numerous “gaps,” and Ford, working with external providers, is on a mission to close as many of them as possible.
“Consider our current design tools,” she said. “Software developers in the industry have done a good job with generative design and topology optimization for AM to inform the idealized placement of material to meet the part’s geometry constraints and functional requirements, but what’s missing is to do so in a way that accounts for anisotropies encountered during the build process, as well as for maximizing printing throughput.”
With that comes the need for better build simulations. Lee explained that today’s product designers put their best foot forward, print a few sample parts, and evaluate the physical results, often building multiple iterations until arriving at the final, optimized design. It’s a time-consuming process, she noted, suggesting that “rapid prototyping” would be much faster if manufacturers could make such iterations in an entirely digital manner. “We need CAE tools able to accurately predict the build process as well as the performance of the printed parts afterward.”
Lee said this capability will be especially important as more equipment manufacturers move away from the current horizontal layer printing approach in favor of multi-axis deposition, as seen in hybrid additive five-axis machining centers and robotic 3D printers, an increasing number of which print polymers. This evolution will open even more doors to automotive engineers at Ford and elsewhere, provided they can design for the process, efficiently generate the required toolpaths, and then simulate the build as just described.
“As with machining, casting, and plastic injection molding, you have to design for 3D printing’s manufacturing constraints,” Lee said. “So how do you make sure that a part is printable when you’re simultaneously moving both the print platform and deposition head in multiple axes, while also trying to meet the part’s packaging and performance constraints? I don’t think the right software tools exist yet to master what some are now referring to as ‘true’ 3D printing.”
Communication is another gap. In the early days of additive, some predicted it would eventually replace many traditional technologies. Now we know that it’s just another set of tools in the manufacturing toolbox—and must therefore “play nice” with its counterparts. To this end, industry needs to do a better job of integrating it into factories and production floors.
For example, AM must communicate with ERP (enterprise resource planning) and MES (manufacturing execution systems), and be easier to automate. Above all, a common language is needed.
“We have so many different providers right now in the additive space and there’s still no widely accepted standard language or file exchange format,” Lee said. “Because of that, communication between them and all the other manufacturing tools in use today is still relatively difficult.”
Difficult or not, Lee and her colleagues are making it work. Ford has invested in multiple AM technologies: metal and plastic powder bed, vat photopolymerization, material extrusion, and binder jet among them. As you might expect, these are used for the usual suspects, such as design development and functional prototyping.
In addition, Lee and her research team are interested in where additive can lend value to the factory floor, for potential production of warranty and service parts, and 3D printing of low-volume custom components. The Holy Grail of AM, though, is scalability toward “automotive level” quantities, what Lee calls “serious production” of vehicle parts.
Before that can happen, researchers must continue making headway on another requirement: eliminating process variability. Granted, it’s a goal shared by all who make parts for a living, but— thanks to 3D printing’s relative immaturity—is of particular concern for those in the AM community.
While conceding that she hasn’t evaluated the entire universe of printer and material combinations, Lee places a sizable share of this variability at the feet of 3D-printer manufacturers. She also emphasized that any who wish to scale their technologies to automotive production levels must do all they can to make their systems as predictable and repeatable as possible.
But the burden of variability reduction also falls on the shoulders of Lee and others with a background in chemistry and materials science. “With powder-bed printing, for example, the particles must be of a specific size and shape if you’re to achieve consistent part quality,” she said. “These and other variables are very dependent on the type of material, the supplier, and what steps they used to make it, but all have an impact on the final product.”
Another critical variable is how much time the feedstock spends in the printer. Lee pointed to a material with some admirable qualities in its virgin form, PA12 nylon, making it one of the most commonly used polymers in selective laser sintering (SLS) powder bed systems. But because each workpiece consumes only a small percentage of the total material contained within the build box, the powder that remains behind must endure repeated heating and cooling cycles, changing its microstructure and mechanical properties.
This situation is exacerbated by the relative shortage of qualified 3D-printing materials. Where plastic injection molders have literally thousands of different chemical compositions to choose from, additive manufacturers have only a few handfuls, many developed to support prototyping rather than functional, end-use products.
The scarcity of materials that meet the automotive world’s stringent requirements further narrows the field. Engineering grade polymers such as PEEK and Ultem, for instance, boast some excellent physical properties but are far too expensive for most vehicle components. Similarly, titanium, cobalt-chrome, and nickel-base super-alloys are great for medical and aerospace uses but are both costly and difficult to machine, the latter of which is a requirement for virtually all 3D-printed metal parts.
The challenge, she said, is the development of materials that meet the wide range of AM applications, followed by standards that govern their use. Referencing her early days with 3D printing and attempting to meet Harold Sears’ reduce, recycle, or reprocess challenge, she’s found it possible to conquer at least some portion of part variability through robust print management.
“If you develop standards for monitoring feedstock usage and therefore controlling their replenishment cycles, you will not only achieve better utilization but also realize improved quality in the finished components,” Lee asserted. “That’s our mission here. We obviously care about producing the best vehicles available, but just as important is to make them affordable to the masses. We see additive manufacturing playing a big role in that going forward.”
It’s a familiar strategy, dating back to the automaker’s origins and Henry Ford’s dictum to build affordable cars for the “great multitude... constructed of the best materials.” While he may not recognize the technology, the Ford patriarch certainly would be proud of AM’s continued innovation and Lee’s ingenuity in developing new applications.
