There are a few basic reasons for the application of lagging to both driven and non-driven pulleys.
- Lagging serves as a protective layer guarding the pulley from premature failure due to abrasion.
- While protecting the pulley, the lagging can also protect the conveyor belting from a similar sort of wear failure caused by abrasion.
- Lagging can also create an increase in friction between the pulley and the belt which is usually needed when there is a requirement for torque transfer through the pulley to the belt.
Lagging is applied to nearly all conveyors to address at least one (if not all) of the basic points above. In addition, lagging should be applied in a way that the lagging itself does not wear prematurely due to abrasion, or delaminating from the pulley, as well as cause belt wear.