The Common Extruder Classification
Posted by Andy
1.Single Screw Extruder
The single screw extruder is the most common extruder, widely used in plastic pipe extrusion, plastic sheet extrusion, plastic profile extrusion, blow molding machine, injection molding machine, and plastic recycling pelletizing field. Here we just discuss its recycling usage.
The single screw extruder normally just use for single plastic waste recycling & pelletizing, like PP/PE/PC/ABS etc. waste. It is simple in design and cheap in price. It adopts involute gear drive, which has the characteristics of low energy consumption, low noise, stable operation, large bearing capacity and long life. But due to its material transport by the screw friction, it’s hard work with powder, paste material, glass fiber and the inorganic filler, and several different materials compounding extrusion. And if the waste is dirty, the die-head of the extruder will always work at high pressure, the melt material will be easy to flow back and come out from the degassing port. And the degassing port of single screw extruder is also not stronger then twin screw extruder. If the waste material has too much dirt and moisture, we have to use the double stage design extruder.
The waste soft plastic film, shopping bag, woven bag etc. using, compactor with double stage single screw extruder line
Waste hard plastic flake, chips etc. using, double stage single screw extruder line
2. Co-rotating Parallel Twin Screw Extruder
As you see from the words, the most important difference between single screw extruder and twin screw extruder is the screw number inside the barrel. Co-rotating twin screw extruder has two tight meshing screws. And due to its modular design of the screw and barrel, it can be easily repaired and adjust the screw combination to achieve the different compounding purpose. But the single screw extruder just has no or only a little different mixing ability. The twin screw extruder has the characteristics of high torque, high rotational speed, and low energy consumption, so it has a unique advantage in the processing of high viscosity, heat–sensitive materials. The complex flow spectra of the materials in twin-screw extruder show the advantages of the single screw extruder in a macroscopic way, for example, full mixing, heat transfer good, melting capacity, strong exhaust capacity and material temperature control good.
Examples of common applications:
- Glass fiber reinforced, flame retardant material granulation (PA6, PA66, PET, PBT, PP, PC enhanced flame retardant, etc.)
- High filling material granulation (PE, PP filled CaCO3, TiO2, Tale etc. )
- Heat-sensitive materials granulation (PVC, XLPE cable materials etc.)
- Color masterbatch (PP, PE, PS, ABS, PC etc. black/white/yellow/red/green/blue color masterbatch)
- Antistatic masterbatch, Alloy, coloring, low filled blending granulation
- Cable material granulation (sheath materials, insulating materials etc.)
3.Conical Twin Screw Extruder
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