Meaning
Compression forces applied to a laminate during cure squeeze out excess resin and eliminate trapped air to achieve a high-quality composite structure. Correct application of consolidation pressure ensures that individual layers of carbon or glass fiber are forced together, establishing a uniform fiber-to-resin ratio throughout the part. This force must be sustained until the resin reaches its gel point to prevent the formation of dry regions.
Insufficient force leads to a high void content, while excessive force squeezes out too much resin and causes dry fibers.
Laminate Densification
Fiber sheets are compressed to their target volume fraction by external pressure that overcomes the mechanical resistance of the dry reinforcement. As consolidation pressure rises, the fiber bed deforms and the individual filaments pack more closely together. This compaction reduces the thickness of the laminate and ensures that the structural fibers are aligned to carry the intended mechanical loads.
Fluid Flow
Liquid resin must migrate through the porous fiber network to fill any empty spaces before it cures. The pressure gradient drives the liquid through the narrow channels between fibers, washing out trapped air and volatiles. If the pressure is not uniform across the surface, resin will pool in low-pressure regions, creating heavy spots that degrade the weight-saving benefits of the composite.
Thickness Control
Dimensional accuracy of the final component depends on maintaining a uniform displacement across the tooling. Tooling boundaries and bag seals must prevent the resin from leaking during the consolidation process. This balance ensures that the finished part meets the strict thickness tolerances required for assembly in aerospace or marine structures.
