**5. Conclusions**

The here presented work is aimed at exploiting the production advantages of L-PBF systems for high-precision applications, in which the design problems pertain to the assembly operations, weight reductions and increasing the sti ffness. In this context, the rails and bracket that support a high-precision flying probe for a testing machine have been redesigned. The redesign is based on a general methodology that considers all the steps of an L-PBF process. The optimization of the design, the support and the part orientation have been driven by material e fficiency. The components that have been redesigned to be produced by L-PBF have demonstrated grea<sup>t</sup> advantages, in terms of mechanical performance. The weight of the rails has been reduced by 32%, while the number of components has been reduced from 16 to 3. The optimized bracket results in being more than 50% sti ffer than the original one and about 10% lighter. In both cases, CAE simulations have shown that grea<sup>t</sup> improvements can be achieved as a result of new material distribution. The results have thus

provided further validation of the fact that an integrated approach between design and AM processes is an extremely powerful tool to generate geometries with high performances and characteristics, even in the case of precision machines, coordinate measuring machines, and industrial robots, in which the mechanical sti ffness of the parts, without any extra weight, is one of the most important design criteria. The cost analysis has also confirmed the suitability of adopting a new manufacturing process to produce components for this industrial sector. The higher cost of the new design of the bracket, with respect to the original one, appears negligible compared to the improvements that can be achieved in terms of component performance and machine accuracy. Additionally, the increased cost appears to be a small part if compared with the market price of these kinds of machines (around €700,000). Compared with the traditional process, DfAM leads to significant savings in material. As a result, the use of AM leads to positive environmental impacts, in terms of material utilization, the supply chain, and life-cycle performances [39].

Overall, AM processes shorten the distance between concept and reality. However, the empirical findings of this study sugges<sup>t</sup> important issues that should be considered in future research:

	- • reach an optimal solution that takes advantage (for specific purposes) of the level of complexity of the design made available as a result of the adoption of AM processes;
	- • achieve the production of truly optimized parts.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2073-4352/10/3/161/s1, Figure S1: Comparison of the Von Mises stress between the original and the new design. As can be observed, the stress on both parts is extremely low. The maximum values around (24 MPa) is registered in the contact between the bolts the rails (Figure S2). The low stresses and grea<sup>t</sup> safety coe fficient respect to the yield stress of the material (503 MPa for the Al7075 of the original design and 350 MPs for the AlSi10Mg of the new design) are due to the high sti ffness requirements which were applied the design stage (which means low deformation and displacements during the working conditions of the system), Figure S2: Localisation of the only areas in which the maximum stress has been registered, Figure S3: Design details of the shaft-hub interference. The features have been designed to guarantee an adequate sti ffness of the connection. This is ensured not only by the feature 'dimensions but also by the roughness of tilted surfaces that is slightly higher of the horizontal and vertical ones and helps to improve the contact between the surface.

**Author Contributions:** Conceptualization, M.G. and L.I.; methodology, M.G. and F.C.; software, M.G. and M.V.; validation, M.G., F.C. and M.V.; formal analysis, M.G.; investigation, M.G.; resources, L.I.; data curation, M.G.; writing—original draft preparation, M.G.; writing—review and editing, M.G. and F.C.; visualization, M.G. and F.C.; supervision, L.I. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Conflicts of Interest:** The authors declare no conflict of interest.
