The French transport technology group Alstom has for the first time qualified a 3D-printed stainless steel doorstop for series production for its train compartments. Alstom worked with the Replique platform to achieve this.

In train construction, small batch sizes often lead to high production costs due to the manufacture of moulds and other tools. 3D printing can avoid fixed costs here and also produce small quantities economically. This advantage has already proven itself for Alstom in the production of spare parts.

To meet a special customer requirement, Alstom needed door stops for a partition door that divides the passenger compartment of a diesel multiple unit into first and second class. The small number of such components is usually an obstacle to initial production. Often there are project delays as a result of long delivery times.

In cooperation with Replique, Alstom was able to qualify and deliver the doorstop for additive series production in one and a half months. In the process, the doorstop went through the protocols of initial sample testing and assembly and received series approval.

The selection of the right material was also crucial here. This is because the door stop must not only fulfil its function over the entire service life of the train, but also meet high aesthetic standards as a visible part inside the train compartment. These requirements were met with stainless steel. The choice here was FDM printing with Ultrafuse 316L from Forward AM, the brand of BASF 3D Printing Solutions, followed by debinding and sintering. Compared to other additive manufacturing processes, the costs were kept significantly lower, according to Alstom.

"We were also able to produce the doorstops in a cost-neutral way compared to conventional manufacturing methods. In the near future, we want to exploit the technology's potential even further by creating topology-optimised designs of new parts, or even make them lighter by using reduced infill," explains Ben Boese, 3D Printing Hub Manager at Alstom Transport Deutschland GmbH.
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