Influence of Infill Pattern on the Elastic Mechanical Properties of Fused Filament Fabrication (FFF) Parts through Experimental Tests and Numerical Analyses

Abstract

Fused Filament Fabrication (FFF) is one of the most extensive additive manufacturing technologies for printing prototypes or final parts in various fields. Some printed parts need to meet structural requirements to be functional parts. Therefore, it is necessary to know the mechanical behavior of the printed samples as a function of the printing parameters in order to optimize the material used during the manufacturing process. It is known that FFF parts can present orthotropic characteristics as a consequence of the manufacturing process, in which the material is deposited layer by layer. Therefore, these characteristics must be considered for a correct evaluation of the printed parts from a structural point of view. In this paper, the influence of the type of filling pattern on the main mechanical properties of the printed parts is analyzed. For this purpose, the first parts are 3D printed using three different infill patterns, namely grid, linear with a raster orientation of 0 and 90°, and linear with a raster orientation of 45°. Then, experimental tensile tests, on the one hand, and numerical analyses using finite elements, on the other hand, are carried out. The elastic constants of the material are obtained from the experimental tests. From the finite element analysis, using a simple approach to create a Representative Volume Model (RVE), the constitutive characteristics of the material are estimated: Young’s Moduli and Poisson’s ratios of the printed FFF parts. These values are successfully compared with those of the experimental tests. The results clearly show differences in the mechanical properties of the FFF printed parts, depending on the internal arrangement of the infill pattern, even if similar 3D printing parameters are used.

Explication of mechanism governing atmospheric degradation of 3D-printed poly(lactic acid) (PLA) with different in-fill pattern and varying in-fill density

“…There are many similar findings 37,70,73,74,84–89 which report in a general sense that as more material is present in the sample, it offers more resistance to deformation. The increase in the in-fill density ultimately increases the number of filament contact points.…”

Deposition of Biocompatible Polymers by 3D Printing (FDM) on Titanium Alloy

“…The 3D FDM prints are mainly tested for their mechanical properties [16][17][18][19]. However, papers analyzing the tribological properties of FDM 3D prints are appearing more frequently [20][21][22][23][24][25].…”

Effect of infill pattern on the mechanical properties of polydopamine‐coated polylactic acid orthopedic bone plates developed by fused filament fabrication

“…Moreover, the distribution of geometry of molten filament deposited in each layer leads to non‐homogeneity of the fabricated structure. [ 30 ] Thus, the infill pattern plays an important role in determining the structure and mechanical properties of the 3D‐printed part. Each type of infill pattern has its own features with varying structures and orientations of deposited material.…”

“…Bonada et al [ 30 ] witnessed improvement in mechanical properties of tensile specimens on changing infill pattern from grid to line pattern (with raster angle 0°/90°) due to complete dense structure of the specimen with raster angle of layers as 0° and 90° alternatively. Dev et al [ 33 ] studied the effect of varying infill densities (20%, 50%, and 80%) and infill patterns (gyroid, honeycomb, and concentric) on mechanical properties of 3D printed ABS structures.…”