KraussMaffei Berstorff, one of the leading extrusion line providers in the world, now offers
extra wear protection for the processing unit of counter-rotating, parallel twin-screw extruders intended for processing polyolefin and polyvinyl chloride (PVC) based natural fiber composites (NFC), according to the company’s statement on June 14.
Processors working with NFC face the ongoing problem of excessive wear, which shortens the service life of the extruder’s plasticizing unit. Increased expansion forces can occur during processing of resin compounds and result in adhesion wear on the screw outer diameter and in the barrel bores.
To reduce this adhesion wear, KraussMaffei Berstorff has adapted the screw geometry to optimize flight and inter-screw clearance. The service life of the processing units is also extended by tungsten-carbide armoring on the screws and bimetallic-plated barrel bores, as stated by the company. When wear does cause problems, processors need only to replace the bimetallic bushing and not the entire barrel, thus reducing costs of operation.
“Wear protection optimized for the material being processed guarantees far longer service lives for the processing units; this minimizes downtime and the associated maintenance costs and loss of productivity,” said Michael Finkenzeller, Product Manager Renewable Raw Materials in the Extrusion Technology Division at KraussMaffei Technologies GmbH.
Apart from adhesion wear, abrasion wear can also be a problem in processing NFC. KraussMaffei Berstorff counters this problem by giving the screws a protective hard chrome plating.
Counter-rotating twin-screw extruders are used worldwide for processing plastics reinforced with natural fibers, for example, wood plastic composites (WPC). Because of their longer life, NFC is replacing pure natural materials in many areas.
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