## 5 Conclusions  
Two nearly identical large-scale LMD machines in terms of the laser source, optics, and powder delivery configuration were compared in the realization of an oil and gas case study. The axis configuration differs significantly between the two machines: one is an eight-axis articulated robot, whereas the other uses a five-axis CNC gantry architecture. On both machines, the same axisymmetric large component was fabricated using the same conventional set of process parameters. In order to compare the geometrical accuracy of the two machines, the deposited components were 3D scanned and compared to the original CAD file. The two 3D scans were also compared to better assess the performance differences between the two machines. * As a result of residual stresses caused by the process, the deposited components deformed toward their centerlines, diverging from the designed part. They both distorted similarly, with no discernible difference between them;
* The geometrical accuracy comparison between the two deposited components revealed no significant discrepancy that could be attributed to the distinct kinematic architecture of the two machines. In the chosen application, the greater accuracy and precision of the CNC gantry system over the articulated robot is not essential. In conclusion, while there were differences in the kinematic architecture of the two large-scale LMD machines used in this study, the comparison of their performance in terms of geometrical accuracy showed no significant discrepancy in the analyzed case study, which is axisymmetric and with a remarkable thickness. Even though the hypothesis is verified on the chosen geometry, this is representative of many components that are typical of the oil and gas field. For this reason, the findings are extendable and applicable to many other elements. For this scenario, the decision between the two systems is not crucial because both machines provided comparable results. Yet, the two systems have distinct advantages and disadvantages. The articulated robot provides greater versatility and can perform a variety of tasks. Furthermore, if the necessity to realize more complicated structures arises, the increased number of axes is advantageous to freeform manufacturing. Finally, relatively low-cost or articulated robots are significant when cost reduction is desired. For these reasons, an articulated robot is clearly the best option in a research setting. On the other hand, a CNC machine is preferred when the easiness of programming is required, as is the robustness and reliability of the system. Hence, this is more applicable to an industrial and production environment. However, it should be considered that the cost of a CNC gantry system may quickly rise when going up with dimensions. Further developments of this work may be related to the examination of more complicated and non-axisymmetric structures than the one chosen for this work. Finally, similar research should be conducted on additional sets of process parameters that increase the deposition rate, as these typically increase the heat input to the material. **Author Contributions:** Conceptualization, S.M., F.C., G.M. and V.F. ; methodology, S.M., F.C., G.M. and V.F. ; software, S.M. ; validation, S.M. ; formal analysis, S.M. ; investigation, S.M., F.C. and G.M. ; resources, G.M. and M.G. ; data curation, S.M. ; writing--original draft preparation, S.M. ; writing--review and editing, S.M. and B.P. ; visualization, S.M. ; supervision, B.P. ; project administration, M.G. and B.P. ; funding acquisition, M.G. and B.P. All authors have read and agreed to the published version of the manuscript. This research received no external funding. **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** Not applicable. **Acknowledgments:** Nuovo Pignone Tecnologie S.R.L. (Baker Hughes) is acknowledged for granting the industrial PhD scholarship which made this research possible, as well as their extensive knowledge and support.