Mixing_Rubber Processing

Mixing
Once the compound ingredients have been weighed out they are mixed together using specialised machines capable of dealing with the high stresses involved in shearing rubber.
Mixing can be either by internal mixing or external/open mill mixing which have very different safety problems.

Internal mixing (eg. Banbury or Intermix mixers)
The compound ingredients are fed into an enclosed mixing chamber via a feed hopper and mixed by the shearing action of two winged rotors and the walls of the mixing chamber. There is therefore a continuous nip.
A powered ram or floating weight in the feed throat forces ingredients into the mixing chamber, which is usually water-cooled. The mixed compound is discharged via a sliding or hinged door below the mixing chamber, usually onto a two- roll mill, roller die, twin-screw extruder, conveyor, skip hoist, or wheeled truck.