The vacuum-assisted process (VAP®) is an infusion technique that makes use of modern semi-permeable membrane systems. As in the case of the conventional VARI process, the dry reinforcement fibre preform is positioned between a fixed-position lower mould and a vacuum set-up topped by a vacuum film. When the cavity between the lower mould and the film is evacuated the liquid resin system is sucked in and cross-links the reinforcement textiles. An integrated semi-permeable membrane offers significant advantages over conventional vacuum infusion processes in terms of evacuation and infiltration, with benefits including enhanced component quality, increased fibre volume content, lower porosity and a significant reduction in reject rates. Its special process characteristics make VAP® technology particularly suitable for large shell-like components and thick-walled structures.