Settlement (permanent deformation)

What is settling?

Settlement in rubber articles is the measure that indicates the permanent deformation.
Permanent deformation (pressure) causes some molecular chains in the elastomer to realign and a few molecular bonds to break. As a result, the elastomer cannot fully regain its original height after being relieved. The difference between the new part and the relieved part is called settlement.

The largest percentage of settling occurs within the first 48 hours under load. This is important when a machine or system needs to be precisely aligned, e.g. boat engine to propeller shaft.