The process is best suited for mid-volume production in the range of 200 to 5,000 parts per year and yields products with high strength-to-weight ratio.
Process
Vacuum infusion typically utilises a mould similar to the one used in hand lay up, but differs in that the reinforcement is placed into the mould dry, covered with an airtight plastic or rubber bag, and upon removing air from under the bag with a vacuum pump, the resin is allowed to "bleed" or infuse into the dry fabric to create the composites.
Very large parts can be made by this method although it requires a very low viscosity resin and a relatively long fill time as well as bleeder film and other venting. The resin infusion process results in very low void content and excellent mechanical properties due to the relatively high glass content.
Materials Options
Resins: Polyester, Vinyl Ester, Epoxy Resin
Fibres: Any
Cores: Balsa, Foam
Advantages
- Preplacement of reinforcement can be employed to achieve optimum strength-weight ratios.
- Best choice for products with high strength-to-weight requirements, or with slight design returns, edge overhangs, or high draft angles that would cause dielocks on rigid B-side mould surfaces.
- Complex multilayer laminates with cores and inserts can be completed in a single step rather than as individual layers.
- In-mould gel coat finishes can be employed for desired cosmetic finishes.
Limitations
- It is more difficult to use this process with filled resins, which are frequently required in construction for building code compliance.
- Cosmetic finish on the surface is not as good as open mould process due to fabric print through; however, a barrier coat can be used to improve the finish.
- Tooling cost is higher.
Applications
- Marine - Hulls, Decks, Reinforcing structures, Mast
- Aerospace - Interior panels, Aircraft Nose Cones, Seats, Radome
- Building & Construction - Bridges, Radio telescopes, Facades (cladding), Swimming pools
- Wind Energy - Turbine Blades, Nacelles, Spinner cones