What are out-of-autoclave (OoA) composite processes and their advantages?

OoA processes cure composites without autoclave pressure. Methods: Vacuum Bag Only (VBO) - Prepreg designed for vacuum-only cure, uses vacuum pressure and oven temperature; Resin infusion (RTM, VARTM) - Dry fiber preform, resin injected or infused under vacuum; Quickstep - Fluid-filled chambers for heat/pressure; and Compression molding - Matched molds for small parts. VBO prepregs: Engineered for low void content without pressure, Higher resin flow, specialized fabrics, and Cycom 5320, Hexcel HexPly M56. Advantages: Lower capital cost (no autoclave), Larger part capability, Faster cycles possible, and Energy savings. Challenges: Achieving void content comparable to autoclave (<1%), Surface quality, and Material qualification. Applications: Secondary structure initially, Primary structure qualification ongoing, and High-rate production (automotive influence). Quality depends on proper processing: vacuum integrity, tool design, and process control. Growing adoption as materials and processes mature.