A plasticising system that combines special component designs and flow surfaces to help injection moulders of optical-grade polycarbonate (PC), acrylic, and similar polymers to produce high-clarity, enhanced-quality parts will be introduced by Nordson Corporation at Fakuma 2015.

The Nordson Xaloy PC Molding System addresses common challenges encountered in moulding optical-grade polymer by delivering a homogeneous melt with a minimum level of the shear that can cause yellowness or discolouration 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 coloured PC for automotive lighting, eyeglasses, optical disks, and electrical and telecommunications components.   

Mark Colella, Nordson Xaloy Global Product Manager, said: "The Nordson Xaloy PC Molding System provides superior quality in critical parts such as lenses by developing a fully homogeneous melt with optimal clarity. As a result, processors can reduce scrap and maximise productivity."

The components of the Nordson Xaloy PC Molding System include:

• Pulsar® II Mixing Screw Modified for Polycarbonate. Nordson has developed a version of the Xaloy Pulsar screw whose design minimises the colour 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.

Hall A6 Stand 6404