bimetallic screw barrel for small plastic injection molding machine

Brand: TENDA

Typee: TD-65
Material: 40CrNiMoA / 42CrMo
Surface roughness: Ra 0.4um
Place of origin: Nanjing
name: Screw and Barrel for plastic extruder machine of twin screw extruder

Different types of screw elements can be used in a twin screw extruder. Generally there are four major types of screw elements, kneading elements, backward-pumping elements and mixing elements. For each type there are many different types.

The geometry of the conveying elements enables a good transport of the product through the extruder. Each conveying element is characterized by its number of flights, its length in millimeters, and its pitch. The pitch is defined as the axial length in millimeters, required for a complete thread. Conveying elements with a large pitch have a greater conveying effect than those with a small pitch. These elements are used to forward the material e.g. at feed openings, in order to avoid that pressure increases excessively at the openings.

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.