What is the working principle of a twin screw extruder

Update:16 Nov 2021

The extruder is an important piece of equipment for plastic processing, and it cannot do without threaded elements in use. Let us understand the principle of the twin-screw extruder and the classification of threaded components.
The principle of twin-screw extruder:
The threaded components of twin-screw extruder accessories mainly include threaded parts, meshing blocks, toothed discs, and so on.
Twin-screw: The screw extruder is a series of basic chemical unit processes, such as solid conveying, pressurization, melting, exhaust, dehumidification, melt conveying and pumping, and other physical processes are concentrated on the screw in the extruder. The machine is carried out. Compared with a single-screw extruder, a twin-screw extruder can make the melt more fully mixed, so it is more widely used.
The barrel of the previous twin-screw extruder is integral and cannot be opened. The split twin-screw extruder is a split type. It consists of an upper and lower barrel. The lower barrel is fixed on the frame, and the upper barrel is connected to the lower barrel through a worm gear reducer. Usually, the upper and lower barrels are fastened with two rows of bolts. When the barrel needs to be opened, just loosen the bolts and turn the handle of the worm gearbox to open the barrel.
Classification of threaded components:
1. Single-head threaded element: Generally used in the feeding section, it has a higher solid conveying capacity. Its function is to transport materials with poor fluidity and to improve the extrusion volume, which is limited by the feeding volume.
2. Double-head screw element: Under the same screw speed, it can provide a lower shear rate, which is more suitable for low bulk density powder glass fiber and other shear-sensitive materials.
3. Three-threaded element: Under the same screw speed, a higher average shear force and shear rate can be applied to the material.
The difference between the three: the output capacity and torque of the single-threaded component are greater than the other two, and the mixing characteristics are more than that of the multi-threaded component; compared with the three-threaded component, the two-threaded component can work at a higher speed, The production capacity is higher; and the three-threaded component has better heat transfer performance than the two-threaded component, which is conducive to physical plasticization and melting.