Radial forming represents a cost-effective alternative to casting and machining for the production of pulleys. Through continuous grain flow and material compaction, strength and hardness are increased, thus saving both material and cost.
The numerous process variants can basically be grouped under the headings of splitting, folding and rolling. In all cases, the sequence of operations is similar and comprises a combination of process steps. A disc blank or a preformed cup is formed in a single cycle whereby the various steps are carried out using specially profiled rollers.
This is a picture of the world's most employed profile spinning machine:
Leifeld HK 60 CNC
Following are two sample parts, which were both produced on Leifeld profiling spinning machines:

Leifeld vertical Profile Forming Center, type PFC 314-V

a multi-V pulley made from a deep drawn cup