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Twin screw rubber extruder machine has three different extrusion systems:
1, non-intermeshing co-rotating twin screw extrusion system
In the non-intermeshing twin-screw extrusion system, in addition to the movement form towards the machine head, there are also many flow modes for the material. Since the two screws are not meshed, the radial gap between them is large, and there is a large leakage flow.
2, intermeshing counter-rotating twin screw extrusion system
The movement of the material in the intermeshing counter-rotating twin-screw extrusion system.
In order to make the material mixing design, leave a certain amount of clearance between the outer diameter of one screw and the root diameter of the other screw, so that the material can pass through. When the material passes through the radial gap between the two screws, it is subjected to strong shearing, stirring and calendering. Therefore, the plasticization of the material is better and it is mostly used for processing products.
3, intermeshing twin screw extrusion system
The flow of materials in the full thread section of the twin-screw extrusion system rotating in the same direction. Because the speed direction of the co-rotating twin screws at the meshing position is opposite, one screw must pull the material into the meshing gap, while the other screw must push the material out of the gap, resulting in the material from one screw to another. The change of this speed and the larger relative speed in the meshing zone are very conducive to material mixing and homogenization.
Twin screw rubber extruder
The extrusion process of twin screw rubber extruder:
The extrusion process of twin screw rubber extruder includes feeding section, melting section, melt conveying section, mixing section, air exhaust section, homogenization section, vacuum exhaust section and metering section.
In the melt conveying section, additives can also be added. Of course, not every extrusion process must include these stages, some have more and some have less, but basically include these stages.
Twin screw rubber extruder
How to combine the screws of the twin-screw rubber extruder:
The screw of twin screw extruder is a modular combination method. The combination of the entire screw should be selected according to the specific formula, material characteristics, mixing requirements, and operating conditions.
First of all, it is necessary to determine the total length of the screw consists of several sections. The so-called sections can be divided by the feeding port and the exhaust port. If there is only one feeding port and no second feeding port or exhaust port, it can be regarded as a section.
If there are two feeding ports or one exhaust port and one feeding port, it is regarded as two stages, and so on. How many stages are used depends on the requirements of the mixing process.