As a continuous and highly automated closed mold process, pultrusion is cost-effective in high volume production  runs of constant cross-section parts. The process relies on a reciprocating or caterpillar-type puller/clamping system to pull the fiber and resin continuously through a heated steel die.

Heat control is a critical part of pultrusion. For this reason, controllers are available to monitor and maintain a pre-set temperature in various zones throughout the die and mandrels. For all-roving pultrusion, a radio frequency (RF) generator can be used to accelerate cure by pre-heating the wet material package. RF energy initiates cure before the material enters the die, reducing cure time and increasing running speed. For example, the running speed for all-roving 1.3 cm rod is about 53 cm per minute. With RF pre-heating, running speed can increase to 25 cm per minute. RF is not generally recommended where mat and/or fabrics are pultruded.

CRAY VALLEY provides both resins and low profile additives for pultrusion.