Analytical and Experimental Investigation into the Relative Influence of Core and Side Parts on Structures Laminated by Fused Deposition Modeling

This work analyzed the effect of the core lattice and side layer (perimeter) on the mechanical behavior of the structures laminated by fused deposition method (FDM) based on analytical and experimental investigation. Since the two parts are the main components that resist external forces, it is important to design the two parts for the FDM-manufactured structures. A tensile test specimen was the target shape in this work because the tensile test specimens have all of the components (top and bottom surfaces, side layer, and core lattice) of the FDM structure. In addition, tensile testing is a useful way to analyze mechanical properties. In order to study the effects of the parameters via the tensile test, specimens were designed with respect to the infill density, raster angle, and side layer thickness. An analytical model was then formulated to understand the measured data, and the presented model was found to have good agreement with the experimental results. The experimental and prediction results showed that the perimeter has a much stronger effect on the FDM structures than the core lattice, except for small raster angle conditions since the core part deforms with rotation mode at the joints, working as a plastic hinge in the core. Additional experiments with special specimens having no side layer also support the idea of a joint effect of the core part. The effects of the process parameters (infill density, raster angle, and perimeter thickness) are also discussed based on the model and experiments. The results indicate that the side layer should be well designed for FDM-manufactured structures to resist external forces.