A process modeling toolkit developed to address scale-up challenges of out-of-autoclave manufacturing

An alternative for manufacturing composite parts out of prepregs, at a reduced cost, is the replacement of the autoclave with a conventional oven or a self-heated tool. In this case, the part consolidation takes place solely under vacuum pressure. This family of processing methods is commonly referred to as Out-of-Autoclave (OoA) or Vacuum Bag Only (VBO) manufacturing. Here we present a modeling framework developed to enable virtual testing of the production cycle, with the ultimate goal the reduction of intra-tow porosity of OoA prepregs. Since Out-of-Autoclave prepregs are typically only partially impregnated, local pressure and temperature inhomogeneity can lead to formation of local air pockets inside the impregnating tows, essentially by cutting them off from the vacuum supply. The importance of ensuring a homogeneous temperature and vacuum distribution, in order to achieve a controlled progression of the tow impregnation during an Out-of-Autoclave cure cycle (OoA) is demonstrated.