3D printing, also known as additive manufacturing, is starting to gain traction in the manufacturing of cars.
Where the process is particularly useful is the manufacturing of complex, low-volume metal parts. Traditionally, complex molds would have to be built and then a foundry would have to cast the parts. With 3D printing, all that's needed is a digital file containing the design, which is then fed into the printer.
Bugatti on Monday detailed how it developed a 3D-printed titanium brake caliper. The automaker says the 8-piston caliper, which is designed for the front axle of the 1,480-horsepower Chiron, is the single biggest 3D-printed car component made from titanium. It measures 16 inches in length and weighs 6.4 pounds. That makes it about 40 percent lighter than the current brake caliper used on the Chiron.
Chirons built to date use forged aluminum alloy brake calipers with titanium pistons (eight front and six rear). With the titanium caliper, Bugatti is using an aerospace-grand titanium alloy normally used for aircraft undercarriage and rocket engines, i.e. highly stressed components. How tough is it? Bugatti says a force of 275 pounds can be applied to a square millimeter of this titanium alloy without the material rupturing.
Bugatti Chiron first drive
Bugatti used a 3D printer equipped with four 400-watt lasers for the caliper. Over a period of 45 hours, titanium powder is deposited layer by layer. With each layer, the four lasers melt the titanium powder into the shape defined for the caliper. The material cools immediately and the caliper slowly takes shape. The total number of layers required is 2,213.
As with casting parts, there is still some refining to do. Heat treatment is carried out in a furnace where the caliper is exposed to an initial temperature of 700 degrees C, falling to 100 degrees in the course of the process, in order to eliminate residual stress and to ensure dimensional stability. Finally, any rough edges are made smooth using a combination of physical and chemical processes.
Bugatti will test the caliper over the course of the first half of the year before installing it on Chirons. Bugatti is also looking at additional 3D-printed components. Another being developed for the Chiron is the cover for the windscreen wiper. At 0.9 pounds, a prototype 3D-printed wiper cover is half the weight of a conventional cast aluminium cover, without any reduction in rigidity.
Note, Bugatti isn't the only hypercar manufacturer taking advantage of 3D printing. Koenigsegg has been 3D printing turbochargers and titanium exhaust components since the launch of its One:1.