Centrale Nantes and SNCF produce a train part by additive manufacturing. A real breakthrough.

Additive manufacturing technologies are of interest in maintenance management in the quest to overcome supply issues, to better manage parts obsolescence, product end-of-life or the slow turnover of components produced traditionally via casting.

Following SNCF's study of SLM* technology (Selective Laser Melting) for metallic materials, their project moved on to assess other manufacturing methods by adding material such as WAAM (Wire Arc Additive Manufacturing) in order to broaden the panel of suitable parts towards larger components and repair.

In 2020, Centrale Nantes and Naval Group used this technology to print the first hollow propeller blade demonstrator. This prompted Laëtitia Kirschner, Additive Manufacturing Project Manager at SNCF Voyageurs, to get in touch with Professor Jean-Yves Hascoët, Head of the Rapid Manufacturing Platform at Centrale Nantes.

After analysing the geometries and constraints of a catalogue of possible components, Centrale Nantes and SNCF opted to use additive manufacturing to produce a pivot, a part that connects the bogie to the carriage.

Centrale Nantes worked on this part, also producing a number of specimens for analysis at SNCF, in order to monitor material integrity, which involved the participation of mechanics specialists and metallurgists in the study. The promising results obtained (metallurgy, mechanical characteristics, etc) on these specimens and tomography on the part itself were sufficiently convincing to proceed to dynamic testing. Given the green light, the part was then submitted to the test bench at the Agence d'Essai Ferroviaire, where it performed successfully under fatigue.

Based on this first study, other projects are in the pipeline for 2021.

Jean-Yves Hascoët: “The collaboration between the laboratory and the SNCF is very encouraging, especially with regard to the input of Additive Manufacturing for maintenance applications. This first step, in this field, raises many opportunities for both establishments.

Laëtitia Kirschner: “WAAM technology is a new milestone for us on the road towards the repair and maintainability of large parts via additive manufacturing. Our fruitful collaboration with Centrale Nantes has made this achievement possible.”

* Additive manufacturing technique specially developed for 3D printing in metal alloys. It creates parts using a high power-density laser to melt and fuse metallic powders together.