Pultrusion is a continuous manufacturing process in which continuous fiber reinforcements are pulled through a resin bath and then through a heated steel die where the profile cures into a solid, constant cross‑section. Typical line speeds range from 0.5 to 2.0 m/min, making it far more productive than batch hand lay‑up. The process yields high‑strength structural shapes such as I‑beams, channels, and solid rods with consistent fibre alignment and high glass content. Because of its efficiency and uniformity, pultrusion is the dominant method for producing FRP walkway supports, cable trays, and structural framing components in industrial construction.
What is Pultrusion: Definition of Continuous FRP Process
Pultrusion is a continuous process for manufacturing fiber‑reinforced polymer (FRP) profiles with a uniform cross‑section, where glass or basalt fiber rovings are pulled through a resin impregnation system and a heated forming die that shapes and cures the material simultaneously.
For example, pultruded structural shapes are regularly used in cooling tower frames where corrosion resistance is critical.
Production Speed vs. Hand Lay‑Up
Compared to open‑mold hand lay‑up, which is labor‑intensive and batch‑oriented, pultrusion runs continuously with minimal manual intervention. A pultrusion line can produce hundreds of linear meters per day, whereas hand lay‑up may yield only a handful of parts per shift of the same volume. This speed advantage makes pultrusion the preferred choice for long‑run structural profiles where part‑to‑part consistency is as important as output rate.
A Typical Process Speed
Standard pultrusion lines operate at pulling speeds between 0.5 and 2.0 meters per minute, depending on profile thickness and resin cure kinetics.
For practical applications of pultruded profiles, see how they perform in FRP structural support systems.
For deeper technical background, see FRP Manufacturing Methods & Comparison.