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Extruder Screw and Barrel & Functions or Advantages of SSE


Extruder Screw :
1. Due to screw rotation the frictional heat is produced .
2. The material flow in the screw channel in a spiral pattern, with the mixing.
3. However, by contrast with the ram extrusion, here the thermal and frictional heat affects continuously  renew the material surface,  thus the thermal degradation is not as severe.
4. The softened material is forced out by the screw.
               *Functions of Single Screw Extruders (SSE)*
1. Plasticating the material (softening,  melting and mixing the melt).
2. Conveying
3. Pressurizing and pumping .
           *Advantages of Single Screw Extruders (SSE)*
1. Uniform heating
2. Continuous process
3. Better mixing than in ram extruder
4. All types of resins can be processed.


Extruder Barrel :
1. Barrel is the cylindrical chamber in which the screw rotates.
2. Hopper is fixed to the top of the barrel.
3. In addition,  barrel may have one or several vents and feed ports.
4. Barrel is provided with band heaters.
5. It is made of hardened steel,  lined with -resistant,  corrosion resistant metal.
6. Barrel materials are complex ferrous alloys of iron,  nickel,  cobalt,  chromium and molybdenum.
7. For PVC materials chromium plated barrel is used (to prevent corrosion).
8. For saran (polyvinylidene chloride) a nickel / chromium alloy is used.

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