The last time we looked at 3D printing in the automotive world, it was still a technique limited to startups like Divergent 3D or Local Motors. But in the last few months, there’s been growing evidence that the big OEMs are waking up to the advantages of additive manufacturing. In recent weeks, we’ve seen Bugatti reveal that it has been 3D printing brake calipers out of titanium, followed soon after by news that Porsche has been using the technique to recreate out-of-stock parts for its classic cars.
Bugatti’s bespoke brakes
In Bugatti’s case, the brand turned to 3D printing to see if it could cut some weight from the front brake calipers on the Chiron hypercar. For the production Chiron, the eight-piston calipers are made from forged aluminum alloy, resulting in a component that weighs 10.8lbs (4.9kg). By comparison, the printed version weighs just 6.4lbs (2.9kg) but manages to have a higher tensile strength. Bugatti turned to Laser Zentrum Nord in Hamburg, Germany for the project.
“Laser Zentrum Nord is one of many scientific institutes with which we have developed very good cooperation over the years,” Frank Götzke, head of New Technologies in the Technical Development Department at Bugatti explained. “Thanks to the large number of projects completed, mainly for the aviation industry, the institute has comprehensive know-how, especially in the field of titanium processing, and offers mature technology.”
Although you can’t currently buy a Chiron that uses the 3D-printed caliper yet, the company is testing the process out on development mules before deciding whether to use it on the $2.9 million cars. “It was a very moving moment for the team when we held our first titanium brake caliper from the 3D printer in our hands,” Götzke said. “In terms of volume, this is the largest functional component produced from titanium by additive manufacturing methods. Everyone who looks at the part is surprised at how light it is—despite its large size. Technically, this is an extremely impressive brake caliper, and it also looks great.”
In addition to brake calipers, Bugatti has been testing the technique out for other parts as well. “We have not only developed the world’s largest titanium component produced by additive manufacturing but also the longest aluminum component to date made by 3D printing,” he said, in reference to a 24-inch (63cm) windscreen wiper, which weighs half as much as one made via die-casting.
Bugatti’s experience also highlights another advantage to additive manufacturing—its speed. “The goal is to let an engineer design a part and print it in the same day,” said Greg Mark, CEO of Markforged Composites, a 3D-printer company based in Massachusetts. (In Bugatti’s case, it takes about 45 hours to print a brake caliper.) “Tools take months; you take the world’s hardest steel and use that to stamp things all day long,” he said. “Instead of starting with a huge block, we start with an empty space, build what we want, and then use a CNC machine to do the last pass to finish it.”
Meanwhile, over at Porsche, 3D printing is being used for a different problem. The company has been building cars for more than 70 years now, and while many of those older machines are still on the roads, not all the old parts are still available. And reproducing them in small batches in the traditional method, with fixed tooling, isn’t really cost-effective. As a result, the company has turned to 3D printing.
If you’re fortunate enough to own a Porsche 959 but unfortunate enough to need a new clutch release lever, Porsche now has you covered. The original part was made from gray cast iron, but Porsche’s spares department will now make you a new one using selective laser melting. Porsche says that “[b]oth the pressure test with a load of almost three tonnes and the subsequent tomographic examination for internal faults were passed by the printed release lever with flying colors. The practical tests with the lever installed in a test vehicle and extensive driving tests confirm the impeccable quality and function of the component.”
Porsche has turned to 3D printing to replicate eight different components that were unavailable, some using metal-alloy selective laser melting, others in plastic via selective laser sintering. The carmaker is exploring whether those techniques will work for a further 20 out-of-stock parts.
In fact, so great is Porsche’s belief in 3D printing as a technique for its future that it recently invested in Markforged Composites. According to CEO Greg Mark, the advantages for a company that builds in relatively low volumes like Porsche or Bugatti are obvious. “Wasn’t the whole promise of technology that we’d have things faster and better?” he asked.
At Porsche’s sister company Volkswagen, which churns out millions of cars each year, the tooling needed to make parts is rapidly amortized to the point where it’s the raw materials that account for your costs. “But when you take a 911 and turn it into a GT3 RS, you’re only making 700 of those a year, and there’s no point making a mold for that. You might as well print it,” Mark told me.
“Porsche knows this because they make low-volume cars. Other OEMs need to retrain their engineers to think when they’re making a low-volume part, they can’t think the tooling is free. If you’re think of bespoke cars, we can print those parts directly. You can print geometries that are lighter than anything you can make any other way. And you can print honeycombed parts, or parts with cooling channels in them; that’s the high-end impact,” Mark explained.
Listing image by Bugatti