3D printed thermoplastic polyurethane bladder for manufacturing of fiber reinforced composites

Abstract

The Bladder Assisted Composite Manufacturing (BACM) technique allows fabrication of complex hollow composite geometries. However, traditional bladder manufacturing methods require multiple steps and a master geometry which increases the cost and the manufacturing time. Hence, additively manufactured bladders are presented as an alternative solution to bladders manufactured through traditional methods. The use of printed bladders is demonstrated by consolidating and curing a composite part made out of an aerospace grade composite prepreg material, IM7/8552. Bladders are additively manufactured using the Fused Deposition Modeling (FDM) technique with Thermoplastic Polyurethane (TPU). Based on the results of a thermomechanical investigation of the TPU, a two-step curing cycle for manufacturing a composite part with IM7/8552 prepreg was designed. The part consolidation achieved with this method was characterized by measuring void content and comparing it to the void content in a sample cured in a standard autoclave process. The low void content achieved with the BACM method demonstrated the potential of this technology for providing bladders for short production runs or prototyping.