This is a dry granulation method. The basic concept is to force fine
powder between the two counter rotating rows due to the force applied on the powders , the volume decreases and the material is formed into a solid compact or sheet. Some of the factors controlling the compaction process are roll surface , diameter , peripheral speed , separating force capabilities , and basic compaction characteristics of the powder being processed . The feed screw controls the flow of the powder in between the rollers.