Influence of the deposition pattern on the interlayer fracture toughness of FDM components

Abstract

The present work is aimed at studying the influence of the deposition strategy on the fracture toughness behavior of the inter-layer zone of fused deposition modeling (FDM) 3D-printed parts. Double cantilever beam (DCB) specimens were produced and tested following recognized testing protocols to capture the fracture toughness behavior. The tested conditions involved linear patterns with monodirectional and alternate infill strategies. The difference in the mechanical behavior of the samples was crossed with optical microscopy observations that also enabled the precise quantification of the effective bonding area between consecutive layers. The results indicated that the deposition pattern dramatically influenced the fracture toughness behavior of these components. Monodirectional deposition strategies involved a fracture toughness within 0.75 and 2.4 kJ/m2 for 0° and 90° raster angles, respectively. On the other hand, the fracture toughness of samples manufactured with alternate deposition strategies more than doubled the values mentioned above, being 2 kJ/m2 and 3.9 kJ/m2 for 0/90° and ±45° deposition strategies, respectively, significantly affecting the failure mode as well. These differences become even more evident if the effective bonding area between consecutive layers is considered.