Plastic extruders can be classified according to the number of screws into single-screw extruders, twin-screw extruders, and multi-screw extruders. Currently, single-screw extruders are the most widely used and suitable for extruding general materials. Twin-screw extruders offer advantages such as less heat generated by friction, more uniform shearing of the material, greater screw conveying capacity, more stable extrusion volume, and longer material residence time in the barrel, resulting in more uniform mixing.
Single-screw extruders hold an important position in both plasticizing and granulation machinery and molding processing machinery, and have seen significant development in recent years.
Twin-screw extruders have good feeding characteristics, making them suitable for powder processing. They also offer better mixing, venting, reaction, and self-cleaning functions than single-screw extruders. They are particularly superior when processing plastics with poor thermal stability and blends. Based on twin-screw extruders, multi-screw extruders, such as the Guanghua Plastics Extruder, have been developed to more easily process blends with poor thermal stability.
1. Based on the number of screws, extruders are classified into single-screw extruders, twin-screw extruders, and multi-screw extruders.
2. Based on whether a screw is present in the extruder, extruders are classified into screw extruders and plunger extruders.
3. Based on screw operating speed, extruders are classified as follows: Standard extruders: speed below 100 r/min; High-speed extruders: speed 100–300 r/min; Ultra-high-speed extruders: speed 300–1500 r/min.
4. Based on the assembly structure, extruders are classified into integral extruders and separate extruders.
5. Based on the spatial position of the screw, extruders are classified into horizontal extruders and vertical extruders.
6. Based on whether venting occurs during processing, extruders are classified into vented extruders and non-vented extruders.
