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General Motors has come a long way since its beginnings over a century ago but one thing has remained constant: its innovative and trailblazing spirit. Over the years, the company has demonstrated its commitment to not only staying on top of automotive trends, but also pioneering them. In 1920, the company developed a game-changing lacquer paint system for cars, which successfully cut production times from weeks to less than a day. In 1963, the company invented the first emissions control device, which quickly became standard across the automotive industry. In the 1970s, GM became the first company to install life-saving airbags in its vehicles. The list goes on. And today, GM’s mission to push the automotive industry ahead continues with the Cadillac CELESTIQ, due out in 2024. Perhaps nowhere is this more evident than when we look at the company’s innovative and boundary-pushing use of additive manufacturing, not only in product development and manufacturing but also production.
3D printing has been on General Motors’ radar since the late 1980s as a rapid prototyping solution, and in recent years, the company’s exploration and production adoption of various additive manufacturing processes has really taken off. You only have to look at one of the company’s latest vehicles, the $340,000 Cadillac CELESTIQ, to understand how far it’s come. The new car, reportedly “the most technologically advanced Cadillac ever”, is described as a “handcrafted, all-electric, ultra-luxury flagship” vehicle. Not only that, it includes over one hundred 3D printed production components.
The Cadillac CELESTIQ integrates 115 metal and polymer 3D printed components, including a metal laser powder bed fusion (LPBF) steering wheel, 3D printed window switches, grab handles, decorative parts, and structural seatbelt D-rings, which holds the title of being GM’s first 3D printed safety-related part. It’s no surprise that the new low-volume vehicle represents the broadest integration of 3D printed production parts for GM. And we wanted to understand how the company got there; how it has pursued AM so successfully and where it’s going with the technology.
Brennon White, Technology Specialist in Additive Design and Manufacturing at General Motors, has generously filled us in on how additive manufacturing fits into GM’s larger vision and how it is helping to shape the company’s vehicle development and production.
A company-wide effort
Brennon White has over two decades of experience in the automotive industry. He spent years working at a Tier 1 supplier specializing in seat work, where he became interested in the potential of additive manufacturing. From there, he joined GM in 2015, where he carried along his strong interest and belief in the technology. “At GM, I started out in the seating group. While I was there, I started doing this kind of grassroots work to figure out what the structure for AM was at GM,” he explains. “And I started running into other people that were doing the same thing. Eventually leadership got wind of what we were doing and from there we put a group together.”
That was five years ago. Today, this AM group has not only helped to spread awareness of the technology across GM’s various divisions, it has made real breakthroughs with how the manufacturing process is used. “It started with us trying to change the way we were thinking about additive at GM and evolved into actually trying to change the way we were looking at it from a production standpoint,” Brennon adds. “From thinking about how to industrialize the technology to now starting to get our stride and push the AM industry into doing things a little bit more aligned with what automotive needs are. That’s been our journey and I love it: it’s what I’m here to do, and we’re starting to do some really cool things.”
According to Brennon, GM on the whole has been incredibly receptive to additive manufacturing as a new production methodology, and the broad support his AM group has received has been vital to its success. “For a company to really make good headway with applying AM, it’s critical that all levels of the company can have ownership of it. We have great benefactors at the executive level, all the way up to President Mark Reuss. For example, when we launched the CELESTIQ recently, he spoke about AM and he was beaming from ear to ear. It’s a cool technology, and the company knows we can do more with it than what we’re doing today. So we have that support.
“It goes even deeper than that: you need leadership that will really absorb and understand additive in order to really challenge teams to think about it as a viable solution,” he continues. “Our chief engineer Tony Roma is awesome on this front. He always refers engineers to me and my team to see if additive could be a beneficial solution and the right way to go.” In other words, AM is kind of always on the table as a potential solution. GM’s additive group works closely with production and manufacturing teams to identify where the technology can offer economic and performance benefits.
The economics of it all
The Cadillac CELESTIQ is a testament that this close-knit dynamic is working. By combining the efforts of various departments and leveraging the knowledge of the AM group, the automotive giant has come up with a very exciting new vehicle that is electric and, most importantly, low volume. This aspect of the vehicle is central to its suitability for AM.
“One of the biggest challenges with additive manufacturing is finding a good economic alignment between the technology and its utilization,” Brennon explains. “There are so many things outside of the manufacturing itself that you have to think about, like overhead, program management costs, and more. When you’re producing at a high volume, those costs are amortized. But at low volumes, like what we’re doing on the CELESTIQ, those costs can become a very big piece of the pie.”
Additive provides an opportunity to achieve low volume while circumventing many of these costs. “At GM, we tend to look at the economics first and if they pass the sniff test, we can go fully into using additive,” he says. “On the CELESTIQ we have 115 parts made using additive. We have metals (aluminum and stainless steel) and polymers (including two types of nylon and polypropylene). Those different materials and the processes that we’re using to make them align with our economics.”
Of course, additive doesn’t only have economic advantages when we’re talking about low-volume production scales. In some cases, it’s the performance benefits that tip the scales in AM’s favor. “We have found parts that can really only be made using additive, and we pay more money for those. The CELESTIQ steering wheel is an example of this. The parts aren’t cheap, but there’s no better way to make them. We looked at multiple different ways of manufacturing the solid metal steering wheel trim and at the end of the day, AM provided a solution that the others couldn’t.”
There are even parts that at first don’t seem to have economic advantages but then upon closer inspection start to make more sense from a cost perspective. “In the polymer space, we’ve found components that initially don’t make sense when we look at the economics, but after discussing with the program team, we’ve come to a different conclusion,” he elaborates. “They’ve told us that they would be scrapping the tool because a particular part is expected to change, so we have to account for the cost of two tools. After that, the economics worked out for AM. So we’re taking a holistic look to make sure we’re making the decision based on multiple factors, not just the short-term economics.”
The AM technologies behind the CELESTIQ
While GM uses a wide array of additive processes across its business, there are a few specific processes that have really excelled for the company’s production applications: metal binder jetting, metal LPBF, and HP’s Multi Jet Fusion.
“The decorative metal parts in the CELESTIQ are mostly made using binder jetting,” Brennon says. “That technology allows us to get a better cost dynamic. Here, post-processing has been really key because that part has to look great. We have also designed a D-ring for the safety belts of the front-row drivers. When we first started looking at them we identified AM as the best way to make them, and throughout their development, we have been able to open up many more opportunities thanks to additive.
“For one, we found that the part it was replacing was actually part of an assembly consisting of a lot of different components. We were able to redesign the part and consolidate five pieces down to one. The steel material we were using was really strong and dense, so we were also able to integrate some hollow features to keep the mass down. In short, Brennon and his team were finding ways to use AM that had not initially occurred to them to enhance the part’s performance and manufacturability.
The CELESTIQ steering wheel, for its part, is made using metal laser powder bed fusion. GM opted to use this process due to its dimensional fidelity and size capacity. “The size of the part somewhat helps to dictate that process we use,” comments Brennon. “Those steering wheel parts are so big that metal LPBF was really the only process that would work properly. Not to mention, it was suitable for achieving the fidelity we needed for the components. The back of the steering wheel has features that go in all different directions, so making a die for it was impossible.”
If we turn to look at polymers, the CELESTIQ integrates a variety of printed parts made using HP’s MJF platform. “The MJF process offers an important balance of mechanical functionality and economics for vehicle components,” he adds.
That’s not to say there aren’t challenges with the technology. “One obstacle throughout the entire AM industry is a lack of automotive grade impact-capable materials. We had additional opportunities to use AM on the CELESTIQ, however, the material performance just wasn’t aligned with our quality standards. This desire for higher performance materials is shared with others in the auto industry, and captured in the United States Council for Automotive Research (USCAR) AM roadmap. .”
The other big challenge is size, particularly in the sphere of polymer AM. “If the print chamber is too small for a part, then we have to get into secondary processes, like assembly, which causes many different challenges from a dimensional standpoint and a joint performance standpoint, as well as from a visual quality perspective.” The need for secondary post-processing is also a challenge with metal AM. Brennon elaborates: “We’re having to do a tremendous amount of work on the post-processing side. There are standard solutions that are on the market today, but they add costs and lengthen the logistics chain, which starts to diminish the benefits of AM, so we’re always looking for better solutions.”
A multi-facility operation
You might be wondering how GM’s additive production functions: where are parts developed, where are they made? As you’d expect, the company has various different facilities, each of which has its own specialty. “We have an R&D facility that does alloy development and a few other specialty things,” Brennon explains. “We’ve got a design fabrication operation that does rapid prototypes that help support the design organization. We’ve got a facility for teaching our thousands of engineers how to think about and use AM. And then we’ve got our group facility, the Additive Industrialization Center (AIC).”
The AIC spans over 15,000 square feet and was first opened in 2020 with the goal of industrializing additive manufacturing in the automotive segment by “pushing the machines to the limit” and working with 3D printer OEMs to improve their systems for automotive needs.
At the Global Technical Center in Warren, Mich., where the CELESTIQ is being made, additive manufacturing has also found an important role. Production 3D printed parts are being shipped in for assembly and a variety of AM tools are utilized to assemble and produce this bespoke vehicle.
At GM, the future of automotive is additive
With the Cadillac CELESTIQ expected to go into production in December 2023, the future for additive within automotive production seems bright. Brennon agrees. “I see a lot of opportunities. At GM, we are trying to help the AM industry appreciate the things we’re going to need in the future, and I see growing adoption of the technology. I see more production utilization and I see AM aiding more in pre-production operations.”
As recently as last November, General Motors (GM) acquired Tooling & Equipment International (TEI), a firm responsible for helping Tesla develop its ‘gigacasting’, a 3D sand printing method for producing large car body parts in a single piece, for ‘less than $100 million’.
GM’s acquisition of TEI signals its intent to manufacture cars more affordably and efficiently. This move comes as Tesla aims to launch a $25,000 electric vehicle (EV) and plans to produce millions of affordable EVs in the next decade. With TEI now under GM, Tesla is relying more on its other sand 3D printing casting partners in Britain, Germany, and Japan, while also reportedly seeking a new sand casting specialist or developing such expertise in-house to reduce dependence on external suppliers.
“In our journey so far – Brennan continues – we’ve mostly been focused on finding applications and figuring out how to make them work. Now, we’re at a point where we’re starting to standardize a lot of these learnings so that we can apply them to other applications and products. We have other vehicles and products—like low-volume variants and trim levels—where we can take what we learned from the CELESTIQ and translate and implement it in a much more efficient methodology.”
Brennon also believes that additive will pave the way for more low-volume opportunities in the automotive industry. “I see us getting better at being able to do low volume and we are continually looking for more transformative applications. There is a lot of space for leveraging the power of AM, especially as we approach the broad use of technologies like batteries and autonomous vehicles, which might require a higher performance part compared to what we used for combustion engines. Additive is going to help us a lot in this space and I am already seeing significant opportunities as we dig into that area.”
If we turn quickly to the topic of mass production, GM is also making good progress. “There is a place for AM in mass production, especially for smaller parts,” Brennon says. For example, GM recently printed 60,000 units of a polymer seal for its SUV trucks. These parts functioned as a bridge solution and enabled the company to meet its production schedule without delays. “We were able to hit 60,000 parts within a couple of weeks and we didn’t stall production at all. Those bridge solutions are something we see as a viable solution going forward, especially if we can get the mechanical properties we’re looking for. It also makes us more agile and more adaptable as an organization.”
Ultimately, the CELESTIQ represents a culmination of hard work and a genuine curiosity about how to implement AM in beneficial ways. But the vehicle also represents a sort of beginning, showcasing that at GM, additive has undoubtedly arrived.
“I’ve been very happy with the way that GM has let our group play,” Brennon concludes. “And I say play because we’re all enthusiasts: we’re learning from each other, we’re developing technologies at an incredible pace, and I feel like we are getting to a place where not only do we understand that we’re going in the right direction, but we’re honing in on making something that’s really going to change how we do business in the future.”
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