ANM (Azienda Napoletana Mobilità S.p.A.), the traditional Neapolitan public transport company, is collaborating with local AM service provider 3DnA to restore and maintain the mobility of its lines in the city of Naples. The production of needed replacement parts was made possible by re-engineering and 3D printing mechanical components no longer available from their supply chain, where the original technical documentation and drawings could not be recovered.
Each trolley bus is connected to the power supply cable lines via a “Trolley Head”, which takes the current and mechanically guides the rods which are fixed on the bus’ roofs. Without a functional Trolley Head, the bus cannot operate.
With no more spare Trolley Heads available on the market, and lead times of more than 12 months with traditional manufacturing methods, the bus fleet would be grounded for months and citizens of the metropolitan city of Naples (3 million inhabitants) would have not been able to access this safe and environmentally friendly means of public transport.
As Ing. Pierpaolo Martino (Director of Operations of Tram&Bus Naples, A.N.M.) heard about the capabilities of additive manufacturing, he contacted Ing. Alessandro Manzo (General Manager of 3DnA Srl.) in order to launch this project aimed at re-engineering and manufacturing the Trolley Heads.
As very little data was available from the original design – apart from some old Trolley Heads in the ANM warehouse – 3DnA carried out a preliminary reverse engineering process via a 3D Laser Scan to reconstruct the Trolley Heads in a 3D modeling software. For the design phase of the 3D printing job, 3DnA used Materialise Magics software (“SG + “and” Simulation” modules), which allowed a considerable optimization of the metal printing process in terms of orientation and support optimization.
A team of engineers from both companies, coordinated by Ing. Mariano Abbate (3DnA) and Ing. Gianluca D’Antona (Maintenance Manager A.N.M.), agreed on the first models and printing of the first prototype, at 3DnA’s AM facility, commenced. 3DnA’s recently renovated 1.000 sqm plant is located in the industrial zone of Pomigliano d’Arco and hosts two of the largest and 3D printing systems in the world.
An SLM500 with 4 lasers from SLM Solutions Group was used for aluminum parts (AlSi10Mg Alloy) while the Fortus F900 FDM system from Stratasys was used for the plastic parts (in ULTEM 9085).
A.N.M tested the prototypes and, in June 2020, they were sent for approval by the Italian Transport Office. Production commenced and, to date, two types of Trolley Heads have been re-engineered and manufactured by the dozens.
“Again 3D printing has proven its worth as a valid alternative technology to traditional means of manufacturing,” explained Alessandro Manzo. “It significantly reduced time to market, to achieve cost savings and greatly increased the ‘convenience’ of component design and production workflow for the companies and engineers involved in the project.”
Thanks to 3D printing, the ANM’s fleet of trolleybuses can keep rolling and continue to provide affordable, sustainable and reliable transportation for the citizens of the beautiful Southern Italian metropolis.