A longitudinal welding system of very long extruded aluminium profiles extended to milling operations, where robot programs are adjusted to workpieces geometry by sensing devices

A joining technology in railways construction is described, related both to: (a) welding process (MIG welds of Al extruded profiles to modules); and (b) to milling operations required on the side walls to fabricate windows, doors or other openings (floor, roof, body shell), using the same gantry robot whose offline programming techniques, thanks to special sensor signals, give the possibility to cover the deviations by means of continuous control and to withstand mechanical shops. In particular the following items are the keys: material used; openings geometry to be machined; milling tools newly designed besides other parameters like adherence to pre-defined relative height torch/workpieces; need to match a rigorous accuracy of the welding modules shape after welding; and precise position of the openings for robots milling operations. Special focus is set to exceptional situations that could induce misuse of the system. The performance criteria commonly applied by Europe's Railways Authorities for process assessment have been taken into account for evaluating the new technology together with the estimated economic advantages.