Naval Group press release
This propeller is a technological exploit. With its 2.5-metre span supported by five 200-kg blades, the equipment left the workshops of the Naval Group site of Nantes-Indret in October 2020 for the site of Brest in order to be mounted on the propeller shaft. As part of its major technical stop, the assembly was transferred to the submarine base to be mounted on the intermediate shaft of the Andromède in November. Sea trials were then performed successfully at the end of December.
A world first for this on-board innovation
“Obtaining military naval quality requires rigorous development. Nearly three years of R&D – carried out by the Technical and Innovation Department in cooperation with the Ecole Centrale de Nantes within the framework of the LabCom Joint Laboratory of Maritime Technology – went into the development of the deposition process of metal wire fusion. Today, we witness a world first. 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.”
Emmanuel Chol, Director of the Nantes-Indret site
The harsh conditions in which ships are used warrant the need to meet strict requirements (corrosion, fatigue, shock resistance, etc.). Naval Group worked together Bureau Véritas throughout the process to present its technical justification file in order to allow the SSF (Fleet Support Services) and the DGA (French Defence Procurement Agency) to authorise the trial of the blades produced on a military ship in normal operating conditions. The blades received certification from Bureau Véritas.
€7 million investment in metal 3D printing in 2021
For Eric Balufin, Director of the Naval Group site of Brest, “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. It will also enable us to greatly reduce production time and consequently in-service support.”
This propeller is a first step. A new development phase will begin, aimed at revamping the detailed design of other parts so that they benefit from 3D printing (acoustic discretion, weight reduction, increased productivity of the parts). For example, 3D-printed production of thrusters will provide ships with greater efficacy at sea: increased thrust efficiency, stealth and lightening.
Naval News comments:
Thanks to metal 3D printing, Naval Group is now able to supply parts to its customer in a shorter time and support and maintenance operations are facilitated because of better reparability and spare parts supply.
This propeller is a first step because it was designed on the basis of the initial design. A new development phase will begin, aiming to rethink the design of other parts so that they benefit from the gains of additive manufacturing (acoustic discretion, mass gain, increased productivity of the parts). For example, the production of thrusters in additive manufacturing will bring greater efficiency to vessels at sea: improved propulsive efficiency, stealth and lighter weight.
The advantages of additive manufacturing for propellers are :
- Reduction of mass, costs and delays;
- Improved performances in acoustic discretion;
- Improved energy performance;
- Improved quality during the manufacturing process