- PC molding system ensures lens-quality clarity and prevents discoloration
- Designed to prevent yellowing and minimize development of black specks
- System includes screw, barrel, valve and endcap
- Nordson at #Fakuma 2015
At #Fakuma 2015, Nordson Corporation will introduce a new plasticizing system that helps injection molders of optical-grade polycarbonate (PC), acrylic, and similar polymers to produce high-clarity parts. The company recommends the system for processing lens-grade or colored PC for automotive lighting, eyeglasses, optical disks, and electrical and telecommunications components.
Designed to prevent yellowing and minimize development of black specks
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.
The components of the PC molding system include:
- Pulsar II mixing screw modified for polycarbonate. The company 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.