1. Application of compaction pressure to consolidate plies and minimize voids
2. Extraction of moisture, solvents, and volatiles
3. Allow the resin to flow and be absorbed
Vacuum Bagging Films are used to seal and provide even pressure to the laminate and tooling surface. Vacuum is applied to ensure compaction, minimize voids, and the removal of volatiles. Vacuum Bagging Film should be of a high quality and possess characteristics such as resistance to tearing, high modulus, high elongation, resistance to “pin holing” and high-temperature resistance. Components, particularly with complex geometries, must be vacuum bagged with plenty of tucks to give ‘depth’ to the film.
The advantages of vacuum bagging are multi-fold and can be identified both structurally and economically. First and most important, vacuum bagging provides equal pressure to all surfaces of the part, whether the part is made up of vertical, horizontal, curved, compound curved or any combination of these. The only limit on the complexity of the part to be bagged is the extent of the planning on the part of the person performing the lay-up process. A uniform external positive pressure and negative internal pressure will aid in expelling air trapped between the core and the laminate thus limiting the possibility of “voids” in the structure.