Screw extruder for continuous extrusion of materials with high viscosity

A screw extruder system for the continuous extrusion of high viscosity metal, the screw extruder system comprising:

• a metal to be extruded;
• a screw housing including an inner liner and an inlet formed in an upstream end of the screw housing for feeding the metal to be extruded;
• an Archimedes screw transporting the metal, the Archimedes screw being rotationally provided within the liner of the screw housing;
• an extrusion die assembly including a die configured to shape the extruded product;
• and
• an extrusion chamber formed between a downstream end of the screw and the extrusion die assembly,
• wherein the screw and inner liner define a compaction zone at a downstream part of the screw towards the extrusion chamber such that compaction of the metal takes place in the compaction zone,
• wherein the compaction zone corresponds to up to 540° of the rotation of the screw, or up to 1.5 turns of the screw flight length, and
• wherein a required compaction and extrusion pressure is obtained by the compacted metal in the compaction zone and a solid plug of metal in the extrusion chamber is restricted from rigid rotation.