A plasticizing system that combines special component designs and flow surfaces helps injection molders of optical-grade polycarbonate (PC), acrylic, and similar polymers to produce high-clarity, enhanced-quality parts by Nordson Corporation will be introduce at Fakuma 2015.
The Nordson Xaloy PC Molding System addresses common challenges encountered in molding optical-grade polymer by delivering a homogeneous melt with a minimum level of the shear that can cause yellowness or discoloration in PC; and by avoiding polymer sticking points or “dead” spots where blemishes such as black specks can form. Nordson recommends the system for processing lens-grade or colored PC for automotive lighting, eyeglasses, optical disks, and electrical and telecommunications components. “The Nordson Xaloy PC Molding System provides superior quality in critical parts such as lenses by developing a fully homogeneous melt with optimal clarity,” said Mark Colella, Nordson Xaloy global product manager. “As a result, processors can reduce scrap and maximize productivity.”
The components of the System include:
Pulsar® II Mixing Screw Modified for Polycarbonate. Nordson has developed a version of the Xaloy Pulsar screw whose design minimizes the color degradation of PC caused by shear during mixing and prevents the sticking of material at sites on the screw where specks can form.
Barrel with X-800® Inlay. Composed of a nickel-based alloy with tungsten carbide, the X-800 inlay provides an especially hard surface with release properties that prevent polymer from sticking to the barrel.
Valve for Free-Flowing Melt Delivery. Nordson provides a valve with internal geometry designed for PC viscosity and recommends different valve types for screw diameters less than 80 mm, screw diameters greater than 80 mm, and flame retardant compounds, respectively. Valves with DyClad™ hard chrome plating are available to provide extra-hard, frictionless surfaces.
Nickel-plated end cap designed to smoothly transition the PC melt from the screw to the injection nozzle
04-Aug-15 
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