In lay-up composite manufacturing, what is the primary purpose of vacuum bagging?

• A. To accelerate curing through heat
• B. To apply uniform pressure, remove voids, and improve resin distribution for better consolidation
• C. To reduce fiber saturation
• D. To improve color uniformity

Answer: (B)

Vacuum bagging applies uniform pressure across the lay-up and helps remove trapped air and excess resin, which improves resin distribution and laminate consolidation. In a lay-up, fibers and resin need to wet out evenly; without pressure, air pockets form and resin can collect unevenly, creating voids and dry spots that weaken the laminate. By pulling a vacuum, the plies are pressed together, air is drawn out, and resin is redistributed more uniformly, leading to better wet-out, fewer voids, and a tighter, more consistent laminate after cure. This isn’t primarily about speeding up curing with heat, controlling a specific resin saturation point, or improving color uniformity.