The difference between twin screw extruder and single screw extruder

1. Plasticizing ability:

- The single screw extruder is suitable for the plasticizing extrusion of polymers and the extrusion processing of granular materials. The shear degradation of polymers is small, but the residence time of materials in the extruder is longer.

- The twin-screw extruder has better mixing plasticizing capacity. The material has a short residence time in the extruder and is suitable for powder addition

2. Material handling mechanism:

- In a single screw extruder, the material transport is drag flow, the solid transport process is friction drag, and the melt transport process is viscous drag. The friction coefficient between the solid material and the metal surface and the viscosity of the melt material largely determine the conveying capacity of the single screw extruder.

- The material transport in twin-screw extruders is positive displacement transport, which means that the material is pushed by the mechanical force between the two screws, thus improving the transport efficiency.

3. Price and structure:

- Single screw extruder has simple structure, low cost and relatively easy maintenance.

- Twin-screw extruders have a complex structure and higher cost, but offer more processing possibilities.

4. Scope of application:

- The single screw extruder is mainly used in the extrusion of pipe, sheet, plate and profile, and some modified materials are granulated.

- Twin-screw extruder due to its good feeding performance, mixing plasticizing performance, exhaust performance, extrusion stability and other characteristics, has been widely used in extrusion products such as glass fiber reinforcement, fuel resistance granulation and so on.

5. Maintenance and operation:

- The twin-screw extruder is easy to open, and the degree of wear of threaded components and barrel lining can be detected at any time, so as to carry out effective maintenance or replacement.

- Single screw extruders may require more time and labor during maintenance.

6. Productivity：

- Twin-screw extruder has large output, fast extrusion speed and low energy consumption per unit production1.

- Single-screw extruders may not be as good as twin-screw extruders in terms of yield and speed.

To sum up, the choice of single screw or twin screw extruder needs to be considered according to the specific production needs, material characteristics, cost budget and maintenance capabilities.