The machines and tools required for spin-flanging are much more complex than those used for die-flanging. In contrast to the classic die-flanging process, spin-flanging forms the flange selectively, only at the points where the flanging rollers come into contact with the body. The body rolls around the flanging rollers, which stretch it into a polygon shape. The flange is formed by the slow penetration of the counter-rotating tools. The body runs along the flanging radius of the flanging rollers and the shoulder of the flanging rollers to the stop ring. The initial polygon shape lasts until a specific flanging width has been reached. Thereafter, the body remains round.
Spin-flanging exerts the lowest stress on the material and the lowest axial load on the neck. This method of flanging is suitable for all neck geometries. |