3D, No Waiting!

July 13, 2023

John Dinkel

Few will dispute that additive manufacturing — commonly called 3D printing — has endured a development path of fits and starts. But as niche applications, an ever-increasing array of material choices — and the innovative specialists nurturing it all — continue to thrive, additive manufacturing continues on a steady track toward its longstanding twin challenges of cost- and throughput-competitiveness with traditional manufacturing processes.

Recently, Automotive Engineering spoke with two key advocates of 3D printing, Los Angeles’ Divergent/Czinger 21C and 3D Systems, based in Rock Hill, South Carolina. Each is executing a unique strategy to explore and advance the future of additive manufacturing.

Divergent CEO Kevin Czinger, along with his COO son, Lukas, are engaged in a long-view effort to reinvent automotive manufacturing from the bottom-up, starting with a chassis built entirely using 3D-printing technology.

The Divergent Adaptive Production System (DAPS) is a complete software-hardware solution designed to replace traditional vehicle manufacturing. It essentially is a complete modular digital factory for complex structures. Given a set of digital requirements, DAPS automatically computationally engineers, additively manufactures and assembles any complex structure. The system is able to switch seamlessly between manufacturing different vehicle models.

DAPS uses generative AI and 3D modeling in the design process. Using additive manufacturing, Divergent can print complex geometries and lighter-weight parts and assemblies. DAPS abolishes casting molds and stamping dies and uses bonding instead of welding. It also eliminates the need for fixtures in the assembly process.

3D Systems, meanwhile, takes a different approach – the company is a one-stop shop for “everything additive.” It not only is a supplier of material, software, hardware and services, but also is a key user. 3D Systems says, “We push the boundaries with expert additive-manufacturing solutions and consultation that make the existing better and the new possible.”

In the automotive sector, 3D Systems touts 58% lower development costs for critical systems and 10 times acceleration of product-development projects. According to Pat Warner, advanced digital manufacturing manager of the Alpine Formula One team, “It’s been exciting to co-develop [with 3D Systems] Accura Composite PIV and see the benefits it’s bringing to our process.”

Particle Image Velocimetry (PIV) is a non-intrusive optical-flow measurement technique used to study fluid flow patterns and velocities. 3D Systems’ Accura Composite PIV is a new material specifically designed to address PIV testing applications used primarily in motorsports wind-tunnel testing. Accura Composite PIV can produce rigid parts in a high-contrast color optimized for PIV testing.

Czinger’s high-performance vision for additive manufacturing

SAE: You’ve called the Blade a demonstration vehicle for a new technology and a new system. How far have you advanced the technology from the 2016 Blade to the 2023 Czinger 21C Hyper car?

Lukas Czinger: For the Blade, we were using AlSi10Mg, which is your standard printable aluminum alloy. Today, we are printing our own material, which is a lot stronger, a lot more durable – and importantly, has much higher elongation for crash. Using AlSi10Mg, I don’t think you’d be able to print a crash-worthy structure.

And on the assembly side, we’ve gone from essentially a concept, bonding – and doing it manually – to a fully robotic-based, fixture-less assembly process.

SAE: What OEMs are you working with today?

Czinger: Aston Martin is now a large customer and I was just in the U.K. and I got to watch our rear frame structure. Visualize 16 large, printed parts assembled into the rear frame of the vehicle – installed on their assembly line into a customer car.

We also work with Mercedes AMG doing large structures. We have about seven other large European OEMs for which we are doing everything from control arms to front frames and rear frames. For some of them, we are even looking at the full chassis now.

We also work in aerospace and defense doing surveillance-drone structures. General Atomics is the first company we started working with. For something like a small UAS (Unmanned Aerial System), instead of taking years to develop a design, [using additive manufacturing] takes months, and instead of taking weeks to manufacture by laying out carbon fiber, we take hours to assemble.

SAE: What are the key advantages of DAPS?

Czinger: The one at the very top is we’ll make a structure that can absorb crash energy as well as the structure the OEM is currently using – but ours is thirty- to forty-percent lighter.

Time savings is a critical advantage. We don’t have a prototype process. You’re never doing soft tooling or a mockup. Our first unit is a production unit. Time to get that first part, even for a complex structure, is six to eight months; OEMs are used to 18 to 30 months for chassis development. Lower development costs and faster development times get an OEM into the market more quickly.

Internally, one of our main objectives is how quickly we can design from scratch something like a vehicle chassis and then get it into production. We’d like it to come down from months to days. That’s going to become incredibly radical for the auto industry. You’re talking about multiple magnitudes of time savings.

SAE: Can you do Class A finishes using 3D printing?

Czinger: Yes. Some areas of the interior: dash inserts, steering column. We can get a very smooth surface and we can anodize our material with different colors or you can paint it. The rims of the 21C have printed, A-surface center spokes.

SAE: What about body panels?

Czinger: Given the amount of mass you would save versus a composite panel, it probably wouldn’t be the right business case for 3D printing. There are unique sheetmetal bending and forming technologies out there that we are looking at as essentially a tool-free way of making the body structure as well.

SAE: Can you provide cost comparisons?

Czinger: Sure. Let’s look at time, at what cost. Our assembly system today is probably four to five times more cost-effective than body-in-white welding. So it actually balances the slightly higher cost of 3D printing.

On the rate side, one 3D printer is capable of doing about one to two kilograms of material per hour. This means within 12 to 16 hours, we can print a large rear frame for an OEM. Today, our highest-volume builds are around 100 units per year. By 2024, we will be in the single-digit thousands. By 2025-2026, it will be tens of thousands and by 2027 hundreds of thousands.

Today, printing two kilograms per hour is 10 times-plus faster than what the rest of the industry is printing at. We have unique printer hardware and software and materials that allow us to print at that differentiated rate. We’ve gone through about a 15-times increase in rate and about a four-times decrease in cost since I started six-and-a-half years ago.

The aluminum material used is critical. Our alloy is about 95% aluminum, which is one of the most abundant and recyclable of metal alloys. The rest is elements that are readily available and process-friendly.

SAE: What about energy usage?

Czinger: When we talk about sustainability, which is one of the Czinger brand pillars, there are really three aspects to it. The first is that we are literally using 30- to 40-percent less material input to get the same performance.

Pillar number two is the actual energy usage designing those parts using HPCs (High Performance Computers) and cloud computing, printing those parts using lasers and assembling those parts with robots, and how that compares to body-in-white castings, stamping, extrusions and welding. Our lifecycle analysis model says we are about 15% more energy- efficient in just the manufacturing process than a typical body-in-white shop.

The last piece is our aluminum-based alloys, which we can readily remelt, atomize and turn into new parts.

SAE: You’re working with Xtrac on gearboxes?

Czinger: We’re doing 3D-printed cases. That has allowed us to integrate some of the cooling into that printed case. It’s a 7-speed AMT and it's electronically actuated; normally, these things are hydraulically actuated. It'll be kind of a world-first for them as well.

SAE: Are you working on any other vehicles subsystems?

Czinger: We call it functional integration, which essentially means taking the vehicle systems like braking or the powertrain or heating motors and tying them into the structure of the car, either hard mounting or with some sort of buffer in between. One example we've shown is a braking system where we're actually printing the caliper directly into the knuckle of the car. So it becomes one piece. You can self-service the brake pads and the rotor quite effectively, but you're passing hydraulic fluid directly into that printed caliper structure and you're integrating it into the knuckle.

We’re going after the EV motor housing, making it structural and getting rid of this box-inside-a-box architecture. We’re also looking at battery boxes to determine if we can integrate the cooling or a battery-management system into the case.

On the 21C essentially all the air systems — engine intake, exhaust — are printed today. We print the headers and exhaust system and our turbo systems are largely printed as well. And now we're starting to look at the core engine block, things like pistons and the block design itself, because as you can probably imagine, handling complex fluid transfers for cooling are is a really good application for unique geometries and packaging.

SAE: Durability testing?

Czinger: There are running cars out there and they're getting quite a few miles onto them. 50,000 miles? No. But we’ve run thousands of miles.

For the 21C, we wanted to build a car that was exceptionally durable. If you wanted to race this car for 24 hours straight, the 21C is a car that from a cooling and a durability standpoint, should have that level of reliability.

SAE: Talk about bonding versus welding, riveting or bolting dissimilar metals.

Czinger: It's a selling point. We developed the adhesive we use to bond large structures. That adhesive is an insulator that's got very low shrinkage and good CTE (coefficient of thermal expansion) properties. Essentially, it allows us to bond dissimilar materials without galvanic interaction. And no concerns regarding expansion or shrinkage of the material.

SAE: How much of the 21C can be recycled?

Czinger: I don't have a percentage off the top of my head, but I'd say near 100% of our chassis should be able to be recycled.

3D Systems: F1 racing highlights broad portfolio

SAE: Speed obviously is of importance to an F1 team – both on the track and for development and testing. Are you producing test pieces as well as production pieces for the racecar via your wind tunnel testing?

Pat Warner: Yes, we use additive in our wind tunnel, for manufacturing aids for the car and for direct components of the car itself. Almost everything you can see [on the F1 car], and quite a lot that you can’t, is produced additively; in the region of 70 percent of the iterative test parts are produced this way.

We produce nearly 500 parts per week for wind-tunnel testing using Accura Composite PIV. Due to the material’s unique optical characteristics, we are now collecting more reliable data from our PIV system in the wind tunnel.

SAE: Are any of these test pieces going into “production” for use on the race car?

Warner: Not directly, the wind tunnel model is scaled down to 60%. Having said that, some of the parts we test on the car on the Friday of an F1 event make their way to race day. These sessions provide most of our opportunities to test on the car during the season.

SAE: How much wind tunnel testing time have you saved via the use of 3D-printed materials?

Warner: I’m not sure that we have saved time in the wind tunnel, but it allows us to deliver more parts in a shorter time, speeding up the process.

SAE: Is the use of 3D-printed components providing weight and space savings on the F1 car?

Warner: Absolutely. The ability to design components without the constraints of conventional manufacturing have helped with packaging on numerous occasions. Our hydraulic inverter coils make a good case-study of this.

SAE: Have you been able to apply the time and cost reductions made via 3D-printing into other areas of the Alpine F1 car to extract more performance from the overall package?

Warner: Absolutely. Last-minute additive parts are quite common. The benefits of being able to produce components without the lengthy process of manufacturing tooling has obvius advantages.

This year we’ll have 22 races. Formula 1 doesn't stay static for very long. It's a big logistics operational challenge. What we're about is pace of development. We require different components at every track. Making them with no tooling involved is obviously ideal for us. 3D Systems gives us a one-stop shop.

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