Non-planar material-extrusion additive manufacturing of multifunctional sandwich structures using carbon-reinforced polyetheretherketone (PEEK)

Additive Manufacturing (AM), and especially Material-Extrusion Additive Manufacturing (MEAM), can provide light structures with high mechanical performances for aerospace applications using fiber reinforced hightemperature resistant thermoplastics (HTRT). Non-planar AM allows to manufacture curved parts with a better approximation of their curvature than cartesian AM. In this paper, we additively manufactured a proof of concept of multi-functional non-planar sandwich panel for aircraft casing using a 6-degree of freedom (6-DOF) robotic platform in a custom heating enclosure, using 30 wt% carbon-reinforced polyetheretherketone (PEEK). Curved beams manufactured using planar and non-planar deposition techniques were manufactured using a custom heating enclosure and reinforced HTRT. The measured surface deviation of the non-planar curved beam (NPCB) was 31% lower than the planar curved beam (PCB). Due to the non-planar deposition that led to a better alignment of the layers along the specimen, the effective stiffness measured during 3-point bending tests was also increased by ~28% compared to PCB, showing the importance of a non-planar deposition. Additively manufactured non-planar sandwich panels containing an acoustic core and two types of microscaffolds (30% infill microscaffold and 74% infill walled microscaffold) were characterized through optical microscopy and 3-dimension (3D) scanner measurements. The 6-DOF robotic platform, combined to the heating enclosure, allowed to print a portion of a non-planar carbon fiber reinforced PEEK sandwich panel to present the versatility of the structures that could be printed with this setup. The use of non-planar reinforced HTRT structures could find applications in the aerospace field for aircraft noise reduction structures, but also in the biomedical domain for the manufacturing of biocompatible PEEK scaffolds.

Mots clés

• Additive manufacturing
• Fused Filament Fabrication
• Non-planar printing
• High-temperature resistant thermoplastics
• Carbon fiber-reinforced composites