Page 19 - 3DA Mag N° February2018 -EN+

For example, even as a 3D printed component, it has caliper was very short. From the first idea to the first
a tensile strength of 1,250 N/mm2. This means that a printed component, it only took about three months.
force of slightly more than 125 kg can be exerted on The basic concept, the strength and stiffness simula-
a square millimetre of this titanium alloy without the tions and calculations and the design drawings were
material rupturing. The new titanium brake caliper, sent to Laser Zentrum Nord by Bugatti as a complete
which is 41 cm long, 21 cm wide and 13.6 cm high, data package. The institute then carried out process
weighs only 2.9 kg. In comparison with the aluminium simulation, the design of the supporting structures, 3D Adept Mag
component currently used, which weighs 4.9 kg, Bugatti actual printing and the treatment of the component.
could therefore reduce the weight of the brake caliper Bugatti was responsible for the finishing touches.
by about 40% while ensuring even higher strength by
using the new part. The special 3D printer at Laser Zentrum Nord, which
was the largest printer in the world suitable for titanium
To date, this approach was not feasible because it is at the start of the project, is equipped with four 400-watt
extremely difficult or even impossible to mill or forge lasers.
components from a titanium block as is normal practice
with aluminium due to the extremely high strength It takes a total of 45 hours to print a brake caliper.
of the material. This problem has now been solved During this time, titanium powder is deposited layer by
using an extremely high-performance 3D printer, which layer. With each layer, the four lasers melt the titanium
also opens up the possibility of generating even more powder into the shape defined for the brake caliper. The
complex structures which are significantly stiffer and material cools immediately and the brake caliper take
stronger than would be possible with any conven- shape. The total number of layers required is 2,213.
tional production process. Frank Götzke found the Following the completion of the final layer, the remaining
selective laser melting units required in Hamburg, at titanium powder which had not melted is removed
Laser Zentrum Nord. from the chamber, cleaned and preserved for reuse

“Cooperation with Bugatti is a key lighthouse project in a closed loop. What remains in the chamber is a
for us,” says Prof. Dr.-Ing. Claus Emmelmann. Prof. completed brake caliper with supporting structure which
Emmelmann Head of the Fraunhofer Institute for maintains its shape until it has received stabilizing heat
Additive Production Technologies (Fraunhofer IAPT) treatment and reached its final strength.
since Laser Zentrum Nord was incorporated in the What remains in the chamber is a brake caliper complete
Fraunhofer research organization. “We were thrilled with supporting structure which maintains its shape until
to be contacted by Bugatti. I do not know any other it has received stabilizing heat treatment and reached
carmaker which makes such extreme demands of its its final strength.
products. We were pleased to face up to this challenge.”
Development time

The development time for the 3D printed titanium brake

Frank Götzke, Head of New Technologies in the Technical Development
Department of Bugatti Automobiles S.A.S.

Magazine / February 2018 19