A B S T R A C TThe effect of SLM parameters on porosity, microstructure and mechanical properties is studied. To this purpose, the Selective Laser Melting (SLM) technology is applied to manufacture Inconel 718 specimens. The material, the manufacturing process, the Hot Isostatic Pressure (HIP), heat treatment, observation procedures and characterisation of mechanical properties are presented. A columnar-dendritic microstructure was observed on all the SLM specimens and a Volumetric Energy Density (VED) effect on the latter was also noted. The rate of porosity varies in relation to the VED and is considerably reduced after HIP. The heat treatment erases the dendritic microstructure, significantly enhances microhardness and confers on the alloy tensile mechanical properties comparable to forged Inconel 718.

Side milling is a process that enables machining time and thus costs, to be reduced. This type of machining is particularly well suited to ruled surfaces and all surfaces where one of the principal curvatures is very small compared to the tool radius and changes little over the entire surface. These surfaces must be treated with great care, as they are often on parts with high added value such as turbine blades, aircraft wings or helicoidal parts as used in fluid dynamics.We then need to calculate and minimise interference that may arise if the ruled surface cannot be developed. Whereas machining is usually carried out by setting the tool according to a rule, we suggest a new setting of the tool allowing interference to be reduced considerably. The computation atgorith~ for this setting were developed so as to be used in real-time by CAD~CAM software.A comparative study of errors made with each type of setting is also presented. This shows a considerable reduction in errors when the setting we suggest is implemented.

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