The open mill is a double roll mill, which uses the shear force generated by two rolls moving relative to each other at different speeds to produce plastic. The operation is to continuously carry out triangle package operation.
The internal mixer uses the regular shrinkage of the space generated by the internal designed blade relative motion to generate the shear force.
The open mill is simple in structure and low in cost, but it is labor-intensive, polluting and harmful to workers.
Internal mixer is more expensive, but it can be heated and vacuumized, and pressurized internal mixer can be used to handle materials that are difficult to plasticize. Low labor intensity and strong adaptability.
The open mill has less mixing capacity, and various mixing doses are easy to add. Moreover, because it is open and has fast heat dissipation, the temperature effect is not so obvious. If the temperature is relatively high, it can be stopped for a period of time and allowed to cool before mixing; The internal mixer may be several times as many as the open mixer. During the mixing process, it is necessary to strictly control the temperature change and the addition order of small materials, which will affect the mixing uniformity and scorching property; In addition, the discharge temperature must be strictly controlled. The temperature difference between the internal mixer and the rubber material temperature is large. Therefore, the temperature relationship must be considered when controlling the temperature, otherwise the rubber material is easy to scorch (generally, the internal temperature of the rubber material is 50-60 degrees higher than the internal temperature of the machine).