during the process of mixing a rubber compound, the compound often heats up. To help keep the rubber compound cool, often one of the rolls is hollow and can be hooked up to a cooling water line which then allows cool water to flow through the roll, cooling the metal roll and therefore the rubber.

While the process of operating a rubber mill sounds simple enough, it is very dangerous and many precautions are added to ensure the safety of the operator. Operators and safety personnel must go through extensive training in order to be certified