The difference between single and twin screw extruder

Views: 171 Author: Site Editor Publish Time: 2021-12-20 Origin: Site

The difference between single and twin screw extruder

Compare the differences between these two extruders in terms of price, operability, and screw.

Item	Single screw extruder	Twin screw extruder
Screw length to diameter ratio (L/D)	Smaller	Longer
Screw section thread shape	Rectangle	Oval
Barrel structure	There are engaging pins on the barrel	The inner surface of the barrel is smooth
Screw temperature control	Cooling inside the screw, easy temperature control	The cooling and sealing in the screw is relatively poor, and the temperature is not well controlled.
Convenience of changing paint varieties and colors	More convenient	OK
The degree of difficulty in processing special powder coatings such as fast curing	Easier	OK
Ease of equipment maintenance	More difficult	Easier
Sensitivity to metal foreign bodies in the material	Sensitive, difficult to process and recycle powder coatings	Not too sensitive

(1) Price of single screw extruder is lower

Single screw extruder has simple structure and low price.

Twin-screw structure is complex and the price is high. The twin-screw extruder is about twice as expensive as the single-screw extruder. Individuals will be higher, depending on the manufacturer and model.

(2) Formula of single screw extruder is simpler

For operation, the difference between the two is actually not very large. However, the process and formula of the single-screw extruder are relatively simple, while the process and formula of the twin-screw extruder are more complicated.

(3) Twin screw extruder can be freely combined with screws

The twin screw extruder can combine screw element at will according to the material. Single screw cannot be configured.

(4) Twin screw extruder is more efficient

The twin-screw extruder has large output, fast extrusion speed and low energy consumption per unit output, while the single screw extruder is worse.

The efficiency of a twin screw extruder is mostly about twice that of a single screw extruder. It depends on the manufacturer and model.

(5) Mixing and plasticizing ability of twin screw extruder is stronger

The single screw is suitable for the plasticization and extrusion of polymers and the extrusion processing of pellets, such as molding, film blowing, injection molding, etc., with a wide range of materials. The twin-screw extruder has good mixing and plasticizing ability, which is more suitable for the modification of plastics. And the twin screw extruder can produce two colors.

(6) Single screw extruder is easy to maintain

In terms of maintenance, the single screw is simpler than the twin screw, because the structure of the single screw is simpler and easy to repair.

(7) Difference in transportation mechanism

The conveying of the single-screw extruder mainly relies on the friction generated between the material and the barrel, and the counter-rotating twin-screw extruder is forward conveying, which has the effect of forcing the material to move forward. In addition, the counter-rotating twin-screw extruder also has a shearing effect on the material at the meshing position of the two screws. (For counter-rotating twin-screw extruder)

Application examples

(1) Application examples of twin screw extruder

Glass fiber reinforced, flame retardant masterbatch (such as PA6, PA66, PET, PBT, PP, PC reinforced flame retardant, etc.), high-filled masterbatch (such as PE, PP filled with 75% CaCO3), Granulation of heat-sensitive materials (such as PVC, XLPE cable materials), High-concentration masterbatch (such as filling with 50% toner), Anti-static masterbatch, Alloy, coloring, low filling blending granulation, Granulation of cable materials (such as sheath materials, insulating materials), XLPE pipe material granulation (such as masterbatch used for hot water crosslinking), Mixing and extrusion of thermosetting plastics (such as phenolic resin, epoxy resin, powder coating), Hot melt adhesive, reactive extrusion granulation (such as EVA hot melt adhesive, polyurethane), K resin, SBS devolatilization granulation, etc.

(2) Application examples of single screw extruder

Suitable for PP-R pipes, PE gas pipes, PEX cross-linked pipes, aluminum-plastic composite pipes, ABS pipes, PVC pipes, HDPE silicon core pipes and various co-extruded composite pipes; Suitable for extrusion of PVC, PET, PS, PP, PC and other profiles and plates, Extrusion of various other plastics such as silk, rods, etc.; Adjusting the speed of the extruder and changing the structure of the extruder screw can be applied to the production of various plastic profiles such as PVC and polyolefins.