In this method, products are made using closed moulds. The first step is to apply the Gelcoat (though production without Gelcoat is possible as well). The next stage is to stack the structural layers (glass mats, synthetic mats, sandwich mats, coremat, roving, etc.) and possible reinforcements and adaptation kits in the mould.
Compressed air and special clamps or actuators or presses are used to apply the appropriate pressure to the mould. As they are subjected to significant closing forces and pressure due to resin injection (during production), any moulds used in this method must have sufficient durability. To this end, we use special pastes, composites and metal frames and reinforcements.
Once the mould is closed, the resin is injected through special openings in it.
- cost-effectiveness for large-volume series,
- low emissions of volatile substances into the environment,
- excellent quality and uniform product structure,
- further reduction of wall thickness thanks to the appropriate mechanical properties,
- high glass content and the highest product durability,
- a smooth, aesthetic surface on both sides (even without Gelcoat),
- highest process efficiency,
- greater material thickness accuracy compared to hand lay-up lamination and LRTM,
- possibility of producing parts with a variable wall thickness,
- low waste and decreased material consumption,
- a very low unit cost of part production but with a higher cost of tooling compared to other technologies mentioned above.
Technical limitations (e.g. technological radii, wall inclination), limitations in terms of size, shape and complexity. The RTM method can be applied to less complex components. The relatively high weight of the tooling limits this method’s applicability in the production of large items. This is only possible with additional tooling and machinery.