The Manufacture of Honeycomb Cores using Fused Deposition Modelling

Sandwich panels are used in many industries, for the advantageous properties of high stiffness, good strength to weight ratio, and impact resistance. Modern manufacturing methods are dominated by manual layup; secondary structure panels often contain multiple core components, complex geometries, and tight placement tolerances. This paper compares cores manufactured using Fused Deposition Modelling (FDM) with conventional Nomex core. FDM is a process of creating complex components from extruded layers of plastic. To analyse the inter-layer bond strength of thin-walled FDM components, tensile behaviour was evaluated for variations in wall thickness. Honeycomb cores were manufactured
using different build patterns, and tested in compression.

It was shown through tensile tests thick-walled FDM components exhibit a more ductile failure with a lower yield point compared to thinner walls. The ultimate tensile stress remained constant across samples. Honeycomb cores produced using FDM were found to have a higher compressive failure force than Nomex, but a lower specific strength. The force-displacement curves of the core failure show a higher energy absorbance of the thicker walled FDM core due to the ductile response.