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Downtime of Neapolitan trolleybuses reduced from 12 months to just two weeks using replacement parts produced using industrial-grade F900 3D printer
Project success leads company to expand service offering to Italy’s nationwide transportation network
Leveraging Stratasys FDM® additive manufacturing, Italian engineering company 3DnA S.r.l is on a mission to transform the way public transport vehicles in Italy are maintained and repaired. Its recent work for Neapolitan public transport company Azienda Napoletana Mobilità S.p.A (ANM) demonstrated first-hand how 3D printing replacement parts on-demand can reduce vehicle downtime by as much as 95% compared to traditional spare part production.
ANM manages the entire public transportation network in Napoli, which includes the city’s famed trolleybuses. The company recently found that many of the buses’ trolley heads – a critical part that connects the aerial power supply line to the trolleybus – were broken or no longer usable. Without a functional trolley head these buses would be rendered inoperable and the service suspended. Due to the age of the trolleybus fleet, the replacement part was no longer available on the market – which not only meant downtime for the bus, but also left the entire fleet at risk in the event of repeat breakages.
Tasked with addressing the problem, 3DnA’s additive manufacturing expertise came to the fore – leveraging its large-scale industrial Stratasys F900® 3D printer to provide ANM a solution.
“Creating the trolley heads with traditional manufacturing processes would have taken up to 12 months, resulting in a lengthy downtime for the vehicle that is simply not an option,” explains Alessandro Manzo, 3DnA’s General Director. “Using our F900, we were able to produce and deliver about 20 of the most critical parts of the trolley head in two weeks, enabling ANM to eliminate further risk of downtime to its fleet and ensure reliable transportation for the three million citizens of Naples. Overall, having this level of production flexibility is extremely important to ANM, as it can now order parts based on actual needs as opposed to warehousing large quantities of costly inventory.”
3D printed part used across entire fleet
With the original trolley head obsolete, 3DnA re-engineered the part using 3D scanning. Importantly, by leveraging the geometric freedom enabled by additive manufacturing, the team was able to re-design the part so that in the event of damage, only a small component of the trolley head would need replacing – not the entire part, as previously.
The new trolley head comprises a core metal structure, with the F900 used to produce the exterior casing that connects the trolley head to the overhead wires. Such has been the impact that it has now become the part of choice for the whole fleet.
“The innovative new design was so well received that ANM has now decided to replace the trolley heads across the entire trolleybus fleet with the new 3D printed version,” continues Manzo. “Without the ability to produce parts with such a high-level of accuracy this would not have been possible. That is where the beauty of the F900 comes in – not only do you get supreme part accuracy, but it’s backed up by a level of repeatability unrivalled in the industry.”
The exterior casing was 3D printed using Stratasys ULTEM™ 9085 resin, providing the structural support required for the rigors of everyday use, while also meeting the necessary electrical insulation standards. Manzo adds: “The part cannot conduct electricity, so having this material is essential. In addition, ULTEMTM 9085 resin provides us three key criteria required for end-use transportation applications: excellent heat resistance with a heat deflection temperature of 153°C, it is a flame-retardant thermoplastic, and offers a very high strength-to-weight ratio.”
Expanding nationwide
Such has been the success in Naples, the management team at 3DnA sees this as the catalyst for transformation of the wider Italian transportation sector.
Manzo concludes: “We believe additive manufacturing will become the prominent spare part production method for the transportation sector. With low volume, on-demand production made cost-effective, the industry is ripe for transformation. Cases like ANM exemplify this, and as a result of this project, we’re already in advanced discussions with several transportation management companies across Italy to support their spare part requirements with this technology.”
