Saertex, the manufacturer of multiaxial fabrics and core materials for the production of fibre-reinforced composites, has produced a prototype of a wind turbine blade with probably the longest carbon fibre spar cap made in vacuum infusion technology so far. Other than Saertex, the prototype production was supported by Windnovation, Composyst and CTP AM.

In April 2019, a wind turbine blade manufacturer in China successfully finished the production of an 87.5m spar cap. The spar cap is one of the key structures inside a rotor blade and takes up most of the mechanical load. The new record spar cap is made of carbon fibre to reduce the part’s weight and achieve higher stiffness which is essential for rotor blades of such extreme length, said Saertex in a press release.

The spar cap was designed by Windnovation. It represented a technical challenge because of its length of 87.5m and its width of 800mm. Materials used for production of the part were the Saertex infusion-optimised carbon fibre UD 618gsm (unidirectional non-crimp fabric) with increased z-permeability material, which had been specially developed for the infusion of thick lay-ups as well as the latent resin system 3325 A/B from CTP AM with optimised viscosity and extended pot-life.

The spar cap was infused in Vaccum Assisted Process (VAP) technology with Composyst's VAP membrane CS/E which enabled degassing of the resin during the entire infusion and eased resin distribution throughout the entire part as well as control of the resin content in the part. This made the entire process safer. The infusion process took less than 2 hours and was completed without any problems. (PC)