What is the principle of a twin screw extruder?


1. Co-rotating twin-screw extruder This type of extrude […]

1. Co-rotating twin-screw extruder
This type of extruder has low speed and high speed. The former is mainly used for profile extrusion, while the latter is used for special polymer processing operations.
(1) Closely meshing extruder. The low-speed extruder has a tightly meshing screw geometry, in which the spiral edge shape of one screw closely matches the spiral edge shape of the other screw, that is, the conjugate screw shape.
(2) Self-cleaning extruder. The high-speed co-rotating extruder has a closely matched spiral shape. This kind of screw can be designed to have a relatively small screw gap, so that the screw has a closed self-cleaning effect. This kind of twin-screw extruder is called a compact self-cleaning co-rotating twin-screw extruder.

2. Counter-rotating intermeshing twin-screw extruder
The gap between the two screw grooves of the tightly meshing counter-rotating twin-screw extruder is very small (much smaller than the gap in the co-rotating twin-screw extruder), so it can achieve positive conveying characteristics.

3. Non-intermeshing twin-screw extruder
The center distance between the two screws of the non-intermeshing twin-screw extruder is greater than the sum of the radii of the two screws.