What is the minimum vacuum requirement when laying up a composite part?

The minimum vacuum requirement when laying up a composite part is typically 22 inches of mercury. This level of vacuum is crucial for ensuring that any air or volatile materials are effectively removed from the composite structure during the curing process. A vacuum of this level helps to consolidate the layers of material, eliminate any potential voids, and enhance the overall strength and integrity of the final product.

In composite fabrication, achieving an adequate vacuum is essential because it directly impacts the quality of the bond between the resin and the fibers. If the vacuum is lower than 22 inches of mercury, it may result in incomplete resin penetration, leading to poor structural performance and the potential for delamination. Therefore, specifying a vacuum requirement of 22 inches ensures that the necessary conditions are met for optimal processing of composite materials.