Flow-forming machines, spin-forming machines capable of flow-forming functions, and mandrels, as follows: a. Machines having both of the following characteristics: 1. Three or more rollers (active or guiding); and 2. Which, according to the manufacturer´s technical specification, can be equipped with "numerical control" units or a computer control; b. Rotor-forming mandrels designed to form cylindrical rotors of inside diameter between 75 and 400 mm.