PlastiComp, a compounder in Winona, Minnesota, is boosting capacity of an interesting, proprietary process to make long-fiber, carbon-reinforced plastic (CFRP) pellets.
The additional, higher-volume carbon fiber pultrusion line will triple PlastiComp’s capacity for producing long carbon fiber products. “In recent years we have experienced continuous growth in demand for our long carbon fiber reinforced composite materials,” said Eric Wollan, vice president and chief operating officer at PlastiComp.
The firm brought its initial production line dedicated to producing long carbon fiber composite pellets online in 2014 and operates four other pultrusion lines to manufacture its long glass fiber products.
The pultrusion process used to make long fiber pellets for injection molding processing is different from the standard thermoset pultrusion process used to make lineal shapes such as ladders. Continuous fiber roving/tow (glass, carbon, or other) is pulled through a pressure die where the fiber tow is spread and melt impregnated with thermoplastic polymer. A compounding extruder operates as a melt pump to feed the molten polymer into the die.
Composite strands exit the die and are cooled into thin composite rods, which we cut into 12 mm (one half inch) pellets to facilitate material handling. If pellets are too long, they clog up the feed throat of the injection molding machine.
PlastiComp makes its own equipment other than the melt pump extruder and the pelletizer
Carbon fiber composites are manufactured by PlastiComp on pultrusion lines located in self-contained areas equipped with isolated electrical and air handling systems.
“From a pultrusion perspective, carbon fiber’s small filament diameter and conductivity makes it a little more challenging to manufacture composite pellets than other types of fiber,” said Wollan. “Using our specialized equipment, PlastiComp is able to completely melt impregnate continuous tows of carbon fiber with 12,000 to 50,000 filaments.”
Plasticomp says that long carbon fiber reinforced thermoplastic composites provide the strongest and stiffest performance available in flowable materials suitable for injection molding processing. PlastiComp’s Complēt pellets contain 15 to 50 percent (by weight) long carbon fiber in thermoplastic matrices ranging from polypropylene to PEEK.
CFRPs offer mechanical performance equivalent to aluminum while providing design-dependent weight reductions up to 50 percent.
Thermoplastic materials incorporating carbon fiber reinforcement are conductive (<10E5 ohms-per-square), providing surface and volume resistivity properties and up to 80 decibels (dB) of shielding effectiveness against electromagnetic interference.
The firm also has a long fiber composites line that combines glass fiber and carbon fiber together into a single pellet.