No expense spared: Bugatti explains how it 3D-prints exotic metal parts

Bugatti deputy design director Frank Heyl told Autoblog his team doesn't balk at using the most expensive materials available, and he meant it. The company described how it 3D-prints titanium and alloy parts to save weight.

Look closely at the back end of the 304-mph Chiron Super Sport 300+ or the agile Chiron Pur Sport and you'll spot 3D-printed titanium components. They're the intricately-designed covers installed over the exhaust pipes; they stick out from the carbon fiber diffuser. Each part weighs four pounds, which makes it 2.6 pounds lighter than the one fitted to the standard Chiron. It's one of the weight-saving measures Bugatti took to create both cars.

Manufacturing the part requires firing up four 400-watt lasers that stack 4,200 individual layers of metal powder on top of each other while fusing them. The part is extremely thin in places but remarkably solid thanks to what Bugatti refers to as a "bionic honeycomb" structure, and it's capable of withstanding temperatures of up to 1,200 degrees Fahrenheit. That might sound like overkill, but keep in mind the cover is on the receiving end of a 1,500-horsepower, 16-cylinder engine. The exhaust system gets really hot, really quickly under heavy acceleration.

Bugatti began using 3D printing in 2018, and now the Chiron Sport, the Divo, the one-off La Voiture Noire, and the Centodieci all use components made with 3D-printed metals. The part that covers the Sport's four visible exhaust tips (there are six in total) is notably manufactured using Inconel 718, a nickel-chrome alloy whose audial resemblance to a mid-engined model is purely coincidental; it's not a blend of molten Porsches. It's a material normally used in gas turbines, the blades attached to airplane engines, space ships, and even rocket engines.

Making the cover takes several days. Engineers scan every part they produce with a computer tomograph to detect air bubbles that can get trapped between the layers during the printing process. If there are none, the part is blasted with a material named corundum, painted, and sent to the Bugatti Atelier in Molsheim, France, where it's checked yet again before it's installed on the car. Few exhaust tips have such a fascinating story to tell.

"The advantage of the 3D printing process lies in the geometric shapes that are possible," said Nils Weimann, Bugatti's head of body development. "It is possible to create very finely wrought, complex forms which would tear if made using other techniques such as forging or forming."

Related: Ford's push to make coronavirus medical gear could hinge on 3D printing

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By Ronan Glon