The blade profile of the sigma blade is such that the viscous mass of material is pulled, sheared, compressed, kneaded and folded by the action of the blades against the walls of the mixer trough. Tangential blade is used for material of higher viscosities such as adhesives, rubber compounds, flush colors, dyes and pigments. Overlapping blade action is used for materials of lighter viscosities such as carbon pastes, clay coating, creams, and ointments. The overlapping blade produces a lower kneading and shearing compared to the tangential blade action. Mixing homogeneity upto 99 percent and better can be achieved using the double arm kneader mixers. The power consumption in sigma blade mixer is higher compared to other types of mixers and can range from 45 to 75 kW/ m3 of mix material.

Materials are charged through the top of the container for a fill volume of 40 to 65 percent of the total volumetric capacity of the mixer. The rotation of the two blades is through a heavy duty drive mechanism consisting of motor, gearbox, couplings and gears. Sigma mixers operate at low tip speeds of 60 – 70 metres per minute. Mixing is accomplished at ambient temperature or under conditions of controlled temperatures, depending on the process requirements. To maintain the desired temperature conditions inside the mixing vessel, the mixer troughs can be supplied with jackets for hot or cold media circulation.