Dry fabric layers are laid into the mould (with or without gelcoat) and held into contact by an adhesive spray-glue or by other techniques. The dry stack of fabric is then covered with peel ply and a vacuum bag. After vacuum is applied and the component has been inspected for bag leaks, pipes connecting the component and the resin pot are opened to allow the resin to flow through the dry fabric stack.

The resin infusion process produces high quality composite components with fibre-volume fractions of over 50% and results in mechanical properties similar to those of out of autoclave prepreg components. Like with prepregs, components have one moulded finish. The production process is most suitable for low to medium volumes and for large components. Components are generally not autoclave cured so that the tooling quality requirements are generally lower than those for autoclave prepreg components. Compared to the RTM process the mould costs are significantly lower. Standard wet lay-up or prepreg tools can be used or modified for use with the resin infusion process. Thick dry fabrics of 1000 to 2500 gsm can be infused which reduces the cutting and lay-up time significantly compared to the prepreg process as the prepreg thickness is limited. Purchasing dry fabric and resin separately also results in material cost savings compared to purchasing equivalent prepregs. Furthermore, the resin infusion process allows for the use of preforms where the dry binded fabric stack is laid-up into a separate mould of low quality, compressed with vacuum and heat and then placed into the high quality mould for infusion and oven cure. Preforming can increase the cycle time considerably and hence reduce per unit tooling costs. Preforming is not possible using prepregs as they glue to the mould. 

Resin infusion requires subsequent edge trimming and generally produces higher scrap levels than prepreg components. The resin infusion process can generally produce components at a lower cost compared with prepreg components. Cored structures can be produced in one shot although the use of honeycomb cores is not really possible.

The resin infusion process is somewhat more complex than other composites production techniques as it requires a good understanding of resin flow through the dry fibre stack to determine the location of the vacuum pipe and resin inlet pipe to avoid scrap. The resin flow can be simulated for complex lay-ups and core placements before resin infusion to avoid scrap. c2i can offer this service through its network of specialty engineering companies.

c2i has expertise in the use of the resin infusion process having produced parts such as car tuning and racing parts, racing seats, satellite communication parts or tooling.