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The advancement in 3D printing techniques has raised the hope to use additively manufactured parts as final products in various industries. However, due to the layer-by-layer nature of AM parts, they are highly susceptible to failure when they are subjected to fatigue loading. This review provides a detailed account of the influence of 3D printing parameters on the fatigue properties of parts manufactured by fused filament fabrication (FFF). Existing standards for fatigue testing of polymers and their limitation for 3D-printed parts are discussed. In addition, the cyclic behaviour of polymers is reviewed, and the impact of 3D printing parameters on the mechanical behaviour of FFF parts under tensile, compressive, flexural, and bending fatigue is investigated according to the published results in the literature. Finally, a summary of the works undertaken and suggestions for future research are provided. The influence of 3D printing parameters on the fatigue performance of prints can be different from that seen in the case of static loading and strongly depends on the fatigue loading type. While cross-over infill patterns, higher infill density, and higher layer height favour achieving higher fatigue strength in all loading types, raster orientation is best to be aligned parallel to the tensile loads and perpendicular to the compressive, flexural, and bending forces. In the case of tensile and flexural loading, Y build orientation yields the best result. Finally, print velocity was found to be less significant compared to other parameters, implying that it can be set at high values for faster printing.

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Powder dynamic compaction is one of the new methods for the production of nanocomposites. In this paper, Al6061/ SiC np nanocomposite is compacted using warm dynamic compaction by simultaneous application of heat and dynamic compressive waves. A comparison between the results of this study and those reported in the literature confirms that the warm dynamic compaction methods are superior to cold dynamic and quasi-static compaction method in densification of nanocomposites especially for high volume fractions of nano particles reinforcement. Mechanical and microstructural characterization of the samples is carried out to investigate the effects of temperature and content level of reinforcement. The results indicate that the increase of nano reinforcement content in warm dynamic compaction leads to reduction of the relative density and increase of hardness and the compressive strength. Moreover, higher compaction temperatures result in enhanced density and lower hardness. It is shown that samples compacted using warm dynamic compaction exhibit lower spring back and ejection force and also the distribution of mechanical properties is significantly more homogeneous. Sensitivity analysis showed that temperature increase has the most effect on homogeneity improvement and reducing dimensional change. Microscopic analyses verified that higher compaction temperature leads to lower porosity and improved metal particle bonding. It seems that agglomeration of nanoparticles and destructive phenomena such as capping and delamination are the main reasons for loss of compressive strength at room temperature. These issues are resolved in warm dynamic compaction by increasing the compaction temperature which leads to better bonding between particles.