Top Composite Fabrication Techniques for 2024

By 2024, the global composites market is projected to reach approximately $130.83 billion. In the United States, glass‑fiber reinforcement alone accounted for a $2.1 billion growth in 2017.

Industries across the board are increasingly turning to composites to achieve lighter, stronger, and more durable components. The choice of fabrication method hinges on the material, design intent, and end‑use application.

Below are the most widely adopted techniques, each offering distinct advantages for specific use cases.

1. Hand Lay‑Up

Hand lay‑up remains the foundational technique for thermoset composites. Craftsmen manually place prepreg or dry fiber plies onto a mold, then apply resin—either by brushing (wet lay‑up) or by spraying—before the stack cures.

2. Open Molding (Contact Molding)

Open molding is a cost‑effective process for fiberglass parts. After treating the mold with a release agent and gel coat, materials are laid over the surface using spray‑up or hand lay‑up. Subsequent compaction, core insertion, and a final spray‑up layer create a robust laminate that cures at ambient temperature.

3. Resin Infusion Methods

To accelerate production and improve part consistency, many manufacturers are shifting from manual lay‑up to automated resin infusion techniques.

Resin Transfer Molding (RTM)

Dry reinforcement is placed in a closed mold, and low‑viscosity resin mixed with catalyst is injected under controlled pressure. The process yields high‑quality parts without the need for an autoclave.

Reaction Injection Molding (RIM)

Unlike RTM, RIM injects resin and catalyst as separate streams. The chemical reaction initiates inside the mold, allowing rapid part formation.

Vacuum‑Assisted Resin Transfer Molding (VARTM)

VARTM leverages a vacuum to draw resin into the preform, eliminating the need for heat or high pressure. Its low tooling costs make it ideal for producing complex, high‑volume parts.

Filament Winding

Filament winding is a continuous, highly automated process that wraps continuous fiber strands around a rotating mandrel. It is cost‑effective and widely used for cylindrical components such as golf club shafts, pressure vessels, and fishing rods.

Pultrusion

Pultrusion feeds dry fiber through a resin bath and then through a heated die, forming a continuous profile that cures in‑line. The result is a smooth, ready‑to‑use component with minimal post‑processing.

Tube Rolling

Tube rolling constructs small‑diameter tapered or cylindrical tubes by laying fiber patterns on a surface and compressing them over a mandrel. Repeating the process builds the tube’s length and imparts bending strength.

Compression Molding

Best suited for high‑volume production of thermosets, compression molding uses sheet‑making compounds to form parts in a heated mold. Automotive manufacturers are exploring carbon‑reinforced sheet molding compounds to exploit superior stiffness‑to‑weight ratios.

Injection Molding

Rapid and low‑pressure, injection molding is ideal for filled thermoplastics. Typical cycle times range from one to five seconds, enabling the production of thousands of parts per hour. Automated BMC injection is increasingly replacing metal castings in certain markets.

Key Considerations for Composite Fabrication

Composite fabrication not only shapes the material but also defines its performance characteristics. Fabricators must prioritize safety by wearing appropriate personal protective equipment and implementing company‑wide monitoring protocols to mitigate health risks associated with fibers and resins.

For more information on selecting the right composite process for your application, contact us today.