Pultrusion is a continuous composite manufacturing process where fiber reinforcements are pulled through resin and a heated die to form high-strength profiles with constant cross-sections. It integrates technical textiles like rovings and fabrics, enabling lightweight, durable, and corrosion-resistant structural components widely used in infrastructure and industrial applications.
Step by Step Guide
- Fiber Feeding (Creel System)
Continuous fibers (rovings, mats, fabrics) are unwound and aligned - Resin Impregnation (Wet-Out)
Fibers pass through resin bath/injection → fully saturated - Preforming Section
Fibers are shaped and excess resin is removed - Heated Die (Core Stage)
- Fibers pulled through heated steel die
- Resin polymerizes (cures) → final shape formed
- Pulling Mechanism
Continuous pulling ensures uniform speed and quality - Cooling & Cutting
Final composite profile is cooled and cut into lengths
Material Used
Fibers (Reinforcements)
- Glass fibers (E-glass, S-glass)
- Carbon fibers
- Aramid fibers
Fabric Forms
- Rovings (continuous filaments)
- Woven fabrics
- Continuous filament mats (CFM)
- Stitched / multiaxial fabrics
Advantages
- Continuous and highly efficient production
- High strength-to-weight ratio
- Excellent fiber alignment
- Superior corrosion and weather resistance
- Consistent quality and dimensional accuracy
Limitations
- Restricted to constant cross-section profiles
- Limited design flexibility for complex geometries
- High initial tooling cost
Applications & End Products
- Structural beams, channels, and angles
- FRP gratings and walkways
- Cable trays and ladder rails
- Utility poles and rebars
- Bridge and infrastructure components
- Window frames and cooling tower parts
Applications & End Products
Pultrusion is preferred when:
- Continuous production of uniform profiles is required
- High strength and lightweight performance are critical
- Corrosion resistance is needed (chemical, marine environments)
- Large-scale production with consistent quality is desired
- Simple cross-sectional geometries are sufficient