In Single-Screw Extruders, Mixing Starts in the Melting Process

The melting process for plasticating, single-screw extruders is also an excellent mixing process. A low level of mixing can occur during pellet blending before being placed in the hopper. But the first major mixing process occurs during melting. Here, the feedstock was a mixture containing 200 parts...

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Bibliographic Details
Published inPlastics Technology Vol. 70; no. 9; pp. 26 - 27
Main Author Spalding, Mark A
Format Trade Publication Article
LanguageEnglish
Published Cincinnati Gardner Business Media Inc 01.09.2024
Subjects
ABS resins
Barrels (extruders)
Beds (process engineering)
Compacting
Low level
Melt pools
Melting
Pellets
Raw materials
Room temperature
Rotation
Shear stress
Single screw extruders
Solidification
Solids
Terpolymers
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Summary:The melting process for plasticating, single-screw extruders is also an excellent mixing process. A low level of mixing can occur during pellet blending before being placed in the hopper. But the first major mixing process occurs during melting. Here, the feedstock was a mixture containing 200 parts of a white ABS terpolymer to one part of black ABS, both in pellet form. The cross section was taken from a Maddock solidification experiment where the feedstock was extruded and then the screw rotation was stopped. Next, full cooling was applied to the barrel. After the ABS was solidified and at room temperature, the screw and plastic were pushed out of the barrel, and the plastic was cut off the screw. The areas that are white were solid, compacted pellets when screw rotation was stopped. The melting process occurred mostly in a thin melt film between the solid bed and the barrel wall. The molten resin was then conveyed to the melt pool by the rotation of the screw.
ISSN:0032-1257
2169-7566