Pultrusion services produce fiber-reinforced plastic (FRP) profiles such as rods, angles, tubes, and sheets by pulling fibers and resins through a heated die in a continuous process. Typically, pultruded products are used in applications that require long lengths and high strengths. Examples of pultrusion include fiberglass-reinforced structural shapes and FRP panels, molded grates, pultruded deck components, and other advanced building composites. Pultrusion services may specialize in the production of fiberglass, fiberglass angle, or fiberglass channel pultrusion; round tube or round bar fiberglass pultrusion; square bar or square tube fiberglass pultrusion; graphite pultrusion; or wide flange beam products.
Pultrusion services differ in terms of capabilities. Typically, however, they use pultrusion machines with two types of pullers: reciprocating and caterpillar. Reciprocating pullers or hydraulic pullers use higher pull forces to produce pultruded parts. This equipment is also suitable for applications that require frequent setup changes. Caterpillar pullers have a continuous, electromechanical system with two rotating tracks. These pultruders may also be used for high volume, repetitive pulling with multiple cavities. Typically, the puller has pneumatic cylinders for clamping and pulling in the same operation. Pultrusion services that use specialized or proprietary types of equipment are also available.
Pultrusion services produce fiberglass gratings, composite panels, carbon fiber sheets, and other pultruded products through a multi-step process. First, they use spools and racks to set-up the fibers for pulling. After exiting the creels, the pultruded fibers are passed through an alignment card that keeps the roving from twisting. Next, pultrusion services use a series of rollers to wet the pultruded material in a resin bath. Examples of pultrusion resins include polyesters, vinyl esters, and epoxies. Loose fibers then enter a pultrusion die and exit as a cured part. Finally, a pulling station uses a set of clamps to grip the cross-section before a cutoff saw makes clean cuts.
Certifications and Quality Requirements
Pultrusion services are located across North America and around the world. They differ in terms of certifications, quality requirements, and industries served. For example, companies that serve the aerospace industry often comply with AS 9100 while pultrusion services that serve the automotive industry may comply with QS 9000. Other quality standards for pultrusion services include specifications from the International Standards Organization (ISO) such as ISO 9001:2000, ISO 13485:2003, and ISO 14001.