Fabrication of sandwich structures by combining automated fiber placement and fused granular fabrication

Abstract

Modern aerostructures display increasingly intricate geometries and complex assemblies, which pose significant manufacturing challenges and often result in production bottlenecks. This study investigates the benefits of combining Automated Fiber Placement (AFP) and Additive Manufacturing (AM), in streamlining the workflow. The objective of this work is to assess the combination of technologies, both in terms of manufacturing feasibility and mechanical performance. A flat sandwich geometry (400 mm x 550 mm) is manufactured, using Fused-Granular-Fabrication (FGF) with PEI/CF for the core, and In-Situ-Consolidated Automated Fiber Placement (ICAT) from LM-PAEK/CF tapes for the skins. A comprehensive test campaign is conducted, including thermal, mechanical and microscopical testing. The face sheets exhibited a compressive strength of 295 MPa during long beam flexure testing, while LM PAEK polymer showed an average crystallinity of 10%. Micro-sections of the sandwich laminate revealed the source of defects, indicating significant margin for improvement. The results highlight the synergies of the two technologies, especially the core to skin adhesion. Despite the process-related challenges, the hybrid approach demonstrates potential in aerospace composite manufacturing.