Single and twin extruders are used in the plastics and polymer industry for various processing applications.
A single extruder consists of a single screw that rotates within a hopper to melt, mix and convey the material being processed.
Melting and blending: The main function of a single extruder is to melt solid polymer materials and evenly mix additives, fillers, or coloring agents.
Conveying and metering: The single extruder screw design facilitates the conveying and metering of the molten polymer. The rotating screw pushes the molten material forward.
Pressure Generation: A single extruder can generate pressure to overcome flow resistance during the extrusion process. The pressure allows the molten polymer to be forced through a mold or shaping tool to create the desired shape, such as a sheet, film, tube, or profile.
A twin extruder, as the name suggests, consists of two parallel screws inside a barrel.
Advanced Mixing: The presence of two screws in a twin extruder increases mixing capacity. This is particularly useful for blend applications where multiple ingredients need to be evenly distributed.
Multi-process configurations: It offers different process configurations such as co-rotation, counter-rotation, and interconnection. It is generally used for blending, Reactive extrusion, demolition, and reactive blending.
Versatility: Twin extruders can be equipped with additional features such as side feeders, vacuum systems, or optional equipment to enable additional processing functions. This versatility expands the range of applications that can be achieved using dual extruders.
In summary, although single extruders are primarily focused on the melting, mixing, conveying, and pressurization of the molten material, there are a number of different types of extruders. But twin extruders provide increased mixing capacity, increased productivity, and versatility as it has two screws. The choice between single and twin extruders depends on the specific requirements of the application, desired mixing, performance production, volume, and type of material to be processed.