Pultrusion

The pultrusion process for manufacturing fibre-reinforced composites is similar to filament winding, as both processes use a DOPAG eldomix to keep an impregnation bath at a constant level. The fibres pass through this impregnating bath. In pultrusion, however, the fibre composite components can be produced as elongated endless profiles, for example in U, T, O or much more complex shapes. These components are mainly used in the automotive or construction industry. They are also installed inside the rotor blades for wind turbines to ensure a higher rigidity of the rotor blade.

In pultrusion, carbon or glass fibres are fed from a roll and passed through an impregnating bath filled with epoxy or polyurethane resin. The fibre composite is subsequently pulled through a heated moulding tool, which has the negative shape of the generated profile. This hardens the fibre composite in an ideal way, resulting in a lightweight but highly resilient composite component with a very high strength.

Alternatively, the current trend is also towards injecting resin into the mould using a higher pressure, similar to the RTM process.

The special features: Pultrusion is one of the few methods by which composite components can be produced as endless profiles. After curing, the pultrusions are continuously pulled and cut to size as required.