To evaluate the introduction of selective laser melting (SLM) for serial application, some features directly related to the components safety and performances are to be deeply analyzed. To this purpose, the present article applies three different types of heat treatment on Ti6Al4V as‐received samples produced by SLM: 1) annealing stress relieving, 2) solubilization super‐β transus, and 3) sub‐β transus followed by a tempering. Then, the related microstructures, mechanical resistance, residual stresses, and corrosion resistance are studied. The results identify a set of heat treatment parameters (super‐β transus followed by tempering), which guarantee the required properties. These samples show equiaxial grains composed of α + β phase, good mechanical properties, a high resistance to corrosion, and residual stresses almost null. Finally, this study confirms that Ti6Al4V made by SLM is applied in the transport field.

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As is well known today, additive manufacturing (AM) is a process of joining materials to make objects from 3D model data as opposed to subtractive manufacturing methodologies which remove material. [1] In general, AM technology allows the manufacturing of parts directly from digital model by depositing the material through a layer-by-layer approach that is digitally controlled. This emerging technology can manufacture metallic components with high precision. Among the main advantages, it can be found freedom of part design, part complexity, lightweighting, part consolidation, and design for specific functions. In light of this, AM technologies could provide an optimal trade-off between the need to increase manufacturing speed for highly customized and complex parts while achieving required mechanical properties with near net shaped components containing fewer defects. All these aspects are of interests in metal AM for aerospace, oil and gas, marine, and transport applications. [2] Among these processes, particularly selective laser melting (SLM) is one of the most used. This is a powder bed fusion process that uses metal powder, mainly for the manufacturing of components belonging to the biomedical and automotive field. [3][4][5] SLM has the great benefit to generate very complex shapes [6] that are often impossible to be produced with the conventional technologies. Thus, near net shape (NNS) parts and undercuts can be now easily created with this new technology. Another SLM benefit could be the creation of internal passages by maintaining a good dimensional control; this could be used, for example, for the integration of cooling channels. A first benefit that can be gathered is the reduction of metalworking operation. In the automotive field, the opportunity to create lightweight components [7][8][9] due to a NNS design is even more important. Indeed, this is one of the most feasible measures to reduce the vehicle emissions [10][11][12] and consequently the traffic-related air pollution. As mentioned earlier, it is clearly the need to modify how engineers think when designing parts; the typical design of traditional subtractive manufacturing processes is very different from the new shapes achievable with AM. [13] Thus, to take full advantage of unique capabilities from AM processes, specific Design for Additive Manufacturing (DfAM) methods are needed. Typical DfAM includes topology optimization and other design methods which can be supported by AM-enabled features. In the automotive domain, SLM is currently limited for the production of prototypes or rare spare parts, while research is moving toward a larger adoption of this technology, [14,15] for example, targeting the production of components for high-end and luxury vehicles.

This work introduces the invention of an alternative camshaft manufacturing method aimed at improving the efficiency of the process and providing a more flexible product. The innovation consists in the Laser Metal Deposition (LMD) of a profile on the shaft in order to realise a coupling stretch where the cam is fixed by interference. Alternative profile materials (1.4404 steel and Inconel 625 alloy) are deposited on a 1.0421 steel tube at different laser power levels and powder flow rate. The effect of the process parameters on the deposited profile is investigated initially through the evaluation of indirect quality attributes, such as deposit dimensions, hardness values, and microstructure. Then the coupling force resulting from the press fit test is evaluated. Finally, the best configuration of this new assembled camshaft is tested with a torsion test rig. Performances of the new assembled camshaft are compared with those of traditional products, leading to the validation of this innovative solution. The preliminary feasibility of the LMD application to the production of an assembled camshaft is demonstrated.