Bending strength measurement of structures printed via fused deposition modeling with different infill patterns

Additive Manufacturing (AM) processes are new ways of producing techniques that work by printing parts layer upon layer using 3D models. AM has some subcategories, which are classified according to the used parent materials. Fused Deposition Modeling (FDM) is a material-extrusion-based technique and is mostly used for rapid prototyping and in some cases for a real servicing part. In the FDM technique, input parent materials are commercial polymers and also, it has some important manufacturing parameters including raster and layer configurations, infill density, layer height, nozzle and bed temperatures, nozzle diameter, and printing speed. Among the mentioned parameters, the infill pattern has a significant effect on the mechanical performance of the FDM products. Thus, the current paper surveyed the effect of five different infill patterns (Grid, Triangle, Wiggle, Fast honeycomb, and Full honeycomb) on the tensile and bending strength of the FDM-Polylactic Acid (FDM-PLA) specimens. Each bending specimen has 50 layers, 10 layers from top and bottom considered solid state, and 30 middle layers printed with the mentioned infill patterns. The results revealed that the specimens that were printed with a Wiggle infill pattern showed the highest values of mechanical properties. For instance, the ultimate tensile strength of the Wiggle and Full honeycomb infill patterns were 43.11 MPa and 28.33 MPa, respectively. However, the Triangle infill pattern presented the highest bending strength (failure load was 9,341 N) and the lowest failure strength was related to the specimens printed with a Full honeycomb infill pattern (failure load was 6,394 N). The obtained results in this paper are comprehensively discussed in the results and discussion section.