Through-Thickness Permeable Prepreg for Robust Vacuum Bag Only Processing

Vacuum bag only processing has been studied for decades as a potential alternative to high cost and low-efficiency autoclave cure. Low pressure cure, however, steers from a lack of robustness. While autoclave quality parts can be produced under ideal conditions, lay-up and cure must be carefully controlled when high compaction pressures are removed. With current out-of-autoclave prepregs, large parts and complex geometries pose manufacturing challenges, with the inability to evacuate trapped air leading to unacceptably high void contents. These drawbacks can be eliminated through the introduction of through-thickness permeability, which facilitates rapid air removal over short distances. In this work, a through-thickness permeable prepreg, termed USCpreg, is compared to a range of commercially available vacuum bag only prepregs on the basis of permeability, bulk factor, and cured laminate quality.