This range of resistance machines permits the joining of metals by a sequence of welds, made one after the other, achieved by the rotation of copper alloy discs. These welders allow either longitudinal or transversal seamwelding – also water tight – of cylindrical containers, fire extinguishers, radiators, heaters, tanks, filters and similar items with excellent quality results. Customised equipment are built to fully meet any specific welding need: also D.C. three phase supply and/or D.C. Medium Frequency (1000 Hz) three phase inverter versions are available on request. In particular Medium Frequency seam welders enable extremely high quality welds at greatly increased welding speeds and represent the ideal solution for joining thin sheets and/or filter nets with very contained deformations.