Similar to RTM, Vacuum Assisted Resin Transfer Molding (VARTM) is typically an open-top mold composite part fabricating method that attaches a vacuum bag to the top of the mold tool and applies vacuum to assist the continuous flow of low-pressure infused resin from one side of the mold to the other. Vacuum removes air from the preform and assists the VARTM machine’s on-ratio metered and mixed flow of degassed air-free resin through the compressed composite fiber preforms below the vacuum bag. The APT VARTM process can provide a 60 to 70% fiber to resin ratio with near zero void content.