wiredinUSA July 2020

Custom-designed Xaloy ® screw and barrel packages from Nordson Corporation can withstand the corrosive effects of fluoropolymers in the extrusion of wire and cable insulation, whilemeeting theprocessing requirements of other materials including fluorinated ethylene-propylene (FEP) and polyvinylidene fluoride (PVDF). Fluoropolymers are among themost corrosive materials for processing in standard extrusion systems. TheNordsonpackages usecorrosion- resistant materials for all components, with custom-designed screws tomeet the differing processing temperatures of FEP and PVDF and the special mixing requirements of the individual customer. The corrosion-resistant materials specified for FEP screws include Inconel ® nickel-chromium alloys for the base metal, and Colmonoy ® nickel-based alloys for the hard-surfacing that is welded onto the wear surfaces of the screw flights. For PVDF screws, the recommended base metal is chrome-plated 4140 HT alloy steel or stainless steel. The barrel that Nordson recommends for use with both screws is lined with Xaloy X-800 ® , a highly corrosion- and abrasion-resistant nickel-based alloy with tungsten carbide. Inconel is used for discharge flanges and feed ports. “While there is growing demand for fluoropolymers in wire and cable because of their extreme heat and chemical resistance, these materials require plasticating systems that resist corrosion,” said Walter Smith, senior extrusion application engineer. “In consultation with customers in the wire and cable industry, we have designed package systems for FEP and PVDF that meet this requirement as well as addressing the special processing characteristics of each polymer.”

Corrosion- resisting extrusion of fluoropolymers

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wiredInUSA - July 2020

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