SCREW EXTRUDERS AND PRESSED POWDER COMPONENTS

摘要

With reference to the figure, an elongate hot-pressed insert (1) is of generally undulate W-shape in transverse cross section. Pairs of identical inserts are clamped together in use so as to define overlapping parallel bores (2, 3) for the twin-screws of a twin-screw extruder. The insert (1) has a wear and/or corrosion resistance and is manufactured by hot pressing powders of metal (nickel-based alloy) and/or ceramic material (TiC and TiN) to a near-net-shape, leaving only insert-mating faces (8) to be machined. The surfaces (2, 3) that define the bores of the extruder barrel require substantially no or even zero machining.