(4) Bending tool:
The bending tool defines the bending radius of the tube. For example, for a 42 mm tube R = 42 x 2 = 84 mm.
(5) Rigid Mandrel:
Rigid mandrels are used for thick-walled pipes and large bending radii.
(6) ball mandrel / mandrel members:
Ball mandrels have at the end of the rigid mandrel, one or more movable balls. Thus, the mandrel supports the tube even deeper in the bow. With ball mandrels thin-walled tubes are bent with small bending radii. The smaller the bending radius and the thin-walled tube, the more balls are used. When using ball mandrels seamless pipes or tubes with smoothed weld are required.
(7) wrinkle:
If, wrinkles accure while bending with a mandrel, the use of a wiper die is necessary. Wiper die´s do not smooth out wrinkle, but prevent the formation of wrinkles. You can often dispense with the use of a wiper die when annealed tubes are bent.
