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J. Diakun


Displacement and deformation of material in the feed zone of single-screw extruders


Polimery 1988, No 7-8, 254


DOI: dx.doi.org/10.14314/polimery.1988.254

Summary

Taking into account the geometrical and kinematic relationships existing in the feed zone of the plasticating system of single-screw extruders, formulas have been derived which Defie the individual components of velocity of material displacement: the axial component deciding about the extrusion eff iciency and the components of displacement in relation to cylinder and screw. It follows from the character of the space of screw channel as well as from the dynamic interactions that there appears deformation of material. This deformation can be described in the form of velocity gradients with regard to the direction normal to screw turns and to the radial direction. Formulas describing these gradients – formula (4) and formula (7), respectively – have beeen derived. Deformation of the material in the feed zone only inconsiderably changes the extrusion efficiency, but it is essential for the energy dissipation. An appropriate utilization of this phenomenon can serve fo r the internal heat generation already in the feed zone and for a uniform melting of material in the whole volume.



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