## 4 Conclusions  
Additive manufacturing is being utilized for advancements in the aerospace and automotive fields. In the case of aerospace structures where the loading is flexural as well as bi-directional in nature, it is vital to ensure structural integrity in both directions. The geometrical parameters play an important role in the determination of the stresses; however, the material properties under the particular loading conditions are also of great significance, as the introduction of anisotropy in components produced by fused filament fabrication (FFF) is a common attribute that affects the mechanical properties of the components. Therefore, in this study, the effects of two important parameters which define the material deposition strategy in the FFF process were evaluated under flexural loading conditions. The results were quantified for the in-plane and edgewise directions in terms of maximum flexural load, flexural strength, and flexural modulus of the material. This helped form the basis of a guideline for the researchers working in aerospace structures via additive manufacturing. The following findings can be concluded from this study:  
* The samples with \(0^{\circ}\) raster angle sustained the highest in-plane and edgewise flexural load among all tested raster angles. The increase in the load carrying capacity at \(0^{\circ}\) was 188% greater than that at \(90^{\circ}\);
* \(0^{\circ}\) raster angle exhibited the highest in-plane/edgewise flexural modulus. In-plane flexural modulus increased by about 148% when the raster angle was changed from \(90^{\circ}\) to \(0^{\circ}\);
* Overall, the edgewise flexural modulus of acrylonitrile-butadiene-styrene (ABS) was lower than the in-plane flexural modulus. However, the trend was similar, i.e., the highest edgewise flexural modulus was also obtained for the \(0^{\circ}\) raster angle;
* For the infill patterns, the percentage difference comparison was used to evaluate the most optimum infill pattern for the flexural loading conditions. This comparison indicated that, for both the flexural load and modulus in both directions, the quarter-cubic pattern was the optimum choice for components such as structural components subjected to bi-directional flexural loading conditions. This is because the quarter-cubic pattern outperformed the tri-hexagon pattern by 89% and 37% in terms of flexural load and modulus, respectively;
* The difference in the properties in the two directions for every parameter indicates that the additive manufacturing processes, especially the FFF process, cause a significant degree of anisotropy in the fabricated components. Hence, this study was of fundamental importance to serve as a guideline where AM for the design of structural components subjected to flexural loading conditions is utilized.  
**Author Contributions:** Conceptualization: G.H., H.Q. and H.W.; Methodology: H.Q., G.H. and R.M.; Validation: M.H., H.Q., M.S. and K.A.; Investigation: M.A., T.S., A.A., G.H., H.Q. and R.M., writing--original draft preparation, H.Q., R.M., M.A., K.A. and G.H.; writing--review and editing: H.Q., R.M., A.A., G.H., M.H., M.S. and M.A.; supervision G.H. and H.W. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research received no external funding.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The data presented in this study are available on request.  
**Conflicts of Interest:** The authors declare no conflict of interest.