Bugatti has succeeded in designing a brake caliper that can be produced by 3D printing for the first time.
And, in a world first, the new caliper is made from the metal titanium.
This milestone was achieved with Laser Zentrum Nord of Hamburg, part of the Fraunhofer research organisation since the beginning of the year.
With this achievement Bugatti has taken the lead in 3D printing within the Volkswagen Group and as an innovator in the international automotive industry.
Trials for the use of the 3D titanium brake caliper in series production vehicles are set to start in the first half of the year.
“Vehicle development is a never-ending process,” Bugatti’s Frank Götzke explained.
“In our continuing development efforts, we are always considering how new materials and processes can be used to make our current model even better and how future vehicles of our brand could be designed.
“As our performance data are often at the physical limits, we are especially demanding. This is why Bugatti always goes at least one step further than other manufacturers in the development of technical solutions.”
Götzke, 48, a machine tool and production technician, holds a degree in engineering and has worked for the Volkswagen group for more than 22 years.
He joined Bugatti in 2001 and played a key role in the development of the Veyron as Head of Chassis Development and in the development of the Chiron in his current position.
Bugatti currently uses the most powerful brakes in the world on the new Chiron.
The brake calipers were an entirely new development, forged from a block of high-strength aluminium alloy.
With eight titanium pistons on each of the front calipers and six on each of the rear units, they are also the largest calipers currently installed on a production vehicle.
But, with the newly developed titanium caliper, Bugatti is breaking new ground.
This particular titanium alloy, with the scientific designation of Ti6AI4V, is mainly used in the aerospace industry, for example in highly stressed undercarriage and wing components or in aircraft and rocket engines.
The material offers considerably higher performance than aluminium.
Development time for the 3D-printed titanium caliper was very short. From the first idea to the first printed component, it took only three months.
The special 3D printer at Laser Zentrum Nord, the largest printer in the world suitable for titanium at the start of the project, is equipped with four 400-watt lasers.
It takes a total of 45 hours to print a brake caliper. During this time, titanium powder is deposited layer by layer. With each layer, the four lasers melt the titanium powder into the shape defined. The material cools immediately and the brake caliper takes shape.
A total of 2213 layers is required. Following the completion of the final layer, the remaining titanium powder that has not melted is removed from the chamber, cleaned and preserved for reuse.
What remains is a brake caliper complete with supporting structure which maintains its shape until it has received stabilising heat treatment and reached final strength.
Heat treatment is carried out in a furnace where the brake caliper is exposed to an initial temperature of 700°C, falling to 100°C in the course of the process, in order to eliminate residual stress and to ensure dimensional stability.
Then the supporting structures are removed and the component is separated from the tray.
In the next stage, the surface is smoothed in a combined mechanical, physical and chemical process which drastically improves its fatigue strength — the long-term durability of the component in later vehicle operation.
Finally, the contours of functional surfaces, such as the piston contact surfaces or threads, are machined in a five-axis milling machine which takes another 11 hours to complete its work.
The result is a delicately shaped component with wall thicknesses between a minimum of only one millimetre and a maximum of four millimetres.
“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.”
The first trials in production vehicles are due to be held in the first half of the year.