Surroundings are good. Czinger 21C’s 1250-hp Czinger 21C engine is unmatched on the roads. The large cockpit with glass and the gaping intakes on either side are aeronautic more than automobile. But, underneath the skin is where it gets really weird. Czinger refers to the BrakeNode, which combines brake-caliper components with suspension components in a singular organic form.
This story originally appeared in Volume 14 of Road & Track.
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The sculpture is perforated and sculpted. It almost looks like something out of an H.R. Giger sketchbook. But it’s not mere lunacy. There’s a method to this madness. “We are fully, functionally integrating the brake caliper and upright structures, which so far is on track to deliver over 40 percent mass and part-count reduction with 25 percent stiffness increase—no compromise and no tooling required,” explains Michael Kenworthy, CTO of AM Technologies at Divergent 3D, manufacturer of the Czinger 21C.
The BrakeNode and many of the 21C’s other components are manufactured using a process colloquially called 3D printing. The process is also known as additive manufacturing. “We literally make part geometries that cannot be economically produced any other way,” Kenworthy says.
Traditional manufacturing techniques like casting, milling, and stamping haven’t changed much since the First Industrial Revolution. Three-dimensional printing is wholly new, an umbrella term for a variety of techniques for creating physical objects from digital designs on a layer-by-layer approach. It was first used in practice during the Eighties. Really, though, it’s only in the past 20 years that the technology has matured to usefulness.
One of these two methods is used in a $300 home-based 3D printer. The more popular one is fused deposition modeling. This printer forces spools plastic filament through heatednozzles like a hot glue gun. As the filament cools down, it hardens and creates layers. Stereolithography is another technology that uses UV light to harden resin one layer at a while.
These simple, cheap techniques produce some great-looking parts. However, at the production-automotive level, finer tolerances and greater durability are necessities. Powder bed fusion is the preferred choice for most professionals. This machine can form parts using powdered materials by bonding them and it is capable of costing upwards to $500,000
“We primarily employ laser powder bed fusion, which involves layer-by-layer, selective laser melting of atomized metal powders,” Kenworthy says. “We are generally printing with layer thicknesses on the order of human hairs, around 50 to 100 micron.”
That’s fittingly exotic, but it has mainstream applications too. In 2021, General Motors had 30,000 Chevrolet Tahoes sitting idle due to a single missing component. A traditional production process for the replacement of a part in GM would have required months. GM whipped the parts up quickly using 3D printers, so the SUVs were in the hands of dealers.
GM’s first production 3D-printed parts were a little more specialized. “The Cadillac CT4-V Blackwing and CT5-V Blackwing were GM’s first production vehicles with printed parts, including the shift-knob emblem, an electrical harness bracket, and two HVAC ducts. The cost-savings of additive manufacturing was also a result. [savings] and efficiency in developing the manual transmission, so you could say manual Cadillacs are around because we have this capability,” explains Brennon White, technical lead for GM Additive Manufacturing.
And there’s more to come. The Cadillac Celestiq won’t only be the brand’s first electric flagship sedan. “We expect it to showcase the broadest use of additive manufacturing in a production vehicle, with more than 100 3D-printed parts that are a mix of structural and visual components,” White says. “This number of parts was made possible by expanding on the learnings from the Blackwing programs.”
Then there’s racing. Brad Keselowski, the 2012 NASCAR Cup champion, has a side gig: Keselowski Advanced Manufacturing (KAM), an engineering company focusing on additive manufacturing and parts simulation. “Additive manufacturing is an engineer’s dream tool, because 3D-printing technology allows us to manufacture part geometries that were never possible before using traditional machining, brazing, and welding techniques,” says Keselowski.
Keselowski, who was just 15 years old, saw his first 3Dprinted part, a plastic intakemanifold, on a race car. KAM specializes in aerospace, such as printing parts for rocket engines, but the company also prints parts for Keselowski’s No. 6 RFK Mustang GT. “Most recently we’ve manufactured a power-steering reservoir with enhanced design and found improved performance at a lighter weight,” he says. “Better yet, we reduced the lead-time development by leveraging rapid iteration for the reservoir design and testing.
“These outcomes are truly stunning,” Keselowski says, “and it’s deeply inspiring to be a part of today’s American manufacturing in the Fourth Industrial Revolution.” The best part is that the industry is still discovering what’s possible. The 21C might look flat in just a few more years.
