Comparison of The Advantages of Two-stage Extruders And Twin-screw Extruders

Double-stage extruder （SP Series） and twin-screw extruder (TSE Series) are the main product series of Kairong Group & Haisi Extrusion. There are big differences between these two models.

In order to solve the mutual restraint of multi-functional areas on a screw, the concept of a two-stage extruder was proposed: That is, the functions of one extruder are separated and completed on two extruders respectively, and the two extruders are connected in series to complete the entire extrusion process.

The first extruder is called the first stage, which mainly completes plasticization and mixing;

The second extruder is called the second stage, which is mainly used for homogenization, pressure reduction, and exhaust at the junction of the two extruders.

The two-stage extruder can be arranged at right angles or in a straight line. The first-stage extruder can be a twin-screw extruder, a single-screw extruder, or other forms of continuous mixer.

1 The material transportation of the single-screw extruder mainly relies on friction, which limits the feeding performance. It is difficult to add powder, paste, glass fiber and inorganic fillers.

2. When the machine head pressure is high, the counterflow increases, which reduces the productivity.

3. The surface renewal effect of single-screw exhaust extruder materials in the exhaust area is small, so the exhaust effect is poor.

4. Single-screw extruders are not suitable for certain processes, such as polymer coloring and thermosetting powder processing.

Twin screw extruder compared to single screw extruder

1 In order to solve the above problems, a twin-screw extruder has emerged. Its extrusion system consists of two screws and barrels that are meshing or non-meshing, rotating in the same direction or rotating in opposite directions. Twin-screw extruders have the following advantages compared with single-screw extruders:

2 Under the same extrusion volume, the residence time of the material in the screw is short. Therefore, it is suitable for coloring and mixing materials that will solidify or agglomerate if they stay for a long time.

3. Good mixing and plasticizing effect, and good whitening function.

4. Good exhaust performance.

5. Low specific power consumption. According to reports, when comparing single-screw extruders and twin-screw extruders with the same output, the twin-screw extruder consumes 50% less energy.

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