A variant of the Archimedes screw can also be found in some injection moulding machines, die casting machines and extrusion of plastics, which employ a screw of decreasing pitch to compress and melt the material. It is also used in a rotary-screw air compressor. On a much larger scale, Archimedes's screws of decreasing pitch are used for the compaction of waste material.
a variant of the archimedes screw can also be found in some injection moulding machines die casting machines and extrusion of plastics which employ a screw of decreasing pitch to compress and melt the material it is also used in a rotary-screw air compressor on a much larger scale archimedes's screws of decreasing pitch are used for the compaction of waste material