In beverage end manufacturing, the Rotary Compound Liner is a critical machine responsible for applying the sealing compound into the curl of the shell. This step plays a vital role in ensuring proper sealing between the can body and the lid during the double seaming process at the filler.

After shells are formed and curled, they are conveyed into the Rotary Compound Liner. Each shell is picked up by a rotating turret and held in place, typically using vacuum. As the turret spins, each shell passes under a nozzle that dispenses a precise bead of compound directly into the curl (also called the "countersink curl"). This compound forms a gasket that enables the can to be hermetically sealed once the end is double seamed onto the filled can.

The consistency, location, and volume of compound applied are critical. Too little compound can lead to seam leaks, while too much may cause compound squeeze-out during seaming. Both scenarios can lead to spoilage, downtime, or product recalls.