2. Kneading elements
Kneading elements are mostly used for dispersive mixing, but they are also used for distributive mixing processes. They consist of kneading discs with a certain thickness. Like the conveying elements there are several parameters by which the kneading elements are characterized. These parameters include the number of flights, the staggering angle between sequential kneading discs (in degrees), direction (clockwise or counter-clockwise) and the element length (in millimeters) . Except for their mixing properties, kneading elements can also be used for devolatilizing and draining of the substance. Kneading elements with a small staggering angle are also capable to forward the material through the extruder, but therefore their axial mixing effect is less intense. In general, kneading elements with a smaller disc width provide a better distributive mixing than those with thicker discs, which provide a better dispersive mixing.
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