Naval Group prints first propeller for powering French warship

PARIS – France’s Andromède mine-hunting ship is now being propelled by a 3D-printed propeller designed and manufactured by Naval Group, the company announced on Wednesday.

Emmanuel Chol, director of Naval Group’s Nantes-Indret site where the propeller was made, said, “It is the largest metal 3D-printed thruster ever to have been manufactured and the first propeller resulting from this technology, embarked on board a military ship and manufactured for use beyond just sea trials.”

Weighing 1 metric ton, the propeller is made of five 200 kg (441 pounds) blades which were manufactured using a wire arc additive manufacturing (WAAM) procedure, less well known than other metal 3D printing techniques but better suited for large-scale applications. It works by melting metal wire heated by an electric arc. The process is controlled by a robotic arm.

The French subsidiary of the Japanese group Yaskawa provided the robots and manufacturing tools for this project.

Naval Group worked with Bureau Veritas to guarantee that the testing, inspection and certification requirements (like corrosion, fatigue, shock resistance) were met so that the Fleet Support Services organization and the DGA French procurement agency could authorize the trial of the blades on a military ship.

The propeller was transferred from the manufacturing site to Brest in October 2020 where it was mounted on the propeller shaft of the Andromède. The ship is one of France’s 10 Tripartite mine hunters built in the 1980s, eight of which – including the Andromède – will not be retired for another decade.

Sea trials in December were successful, so now the mine-hunter can return to normal operations, equipped with its printed propeller.

Eric Balufin, director of Naval Group’s site in Brest says “the assembly of this 3D-printed propeller shows great promise for the future. This new technology will enable us to considerably reduce technical constraints, and therefore allow for new manufacturing solutions for complex geometrical shapes which cannot be produced through conventional processes.”