The quality of metallic additive manufacturing outputs is heavily dependent on the employed processing parameters. Hence, the assessment and definition of the input variables appropriate to the material in question is of vital importance, in order to optimise the attainable properties and minimise wasted feed stock in failed trials. In this work, optimal parameters for 18Ni300 Maraging steel are found for deposition in an H13 substrate. Additinally, the influence of pre-heating in depositions on a DIN CK45 steel are analysed by optical microscopy (OM) and microhardness measurements along the interface, and mechanical characterisation of DED-produced 18Ni300 is performed, as well as a bi-metallic alloy comprised of 18Ni300 and CK45, through the production and testing of tensile specimens.

The mechanical behaviour of as-built DED-produced 18Ni300 Maraging steel was studied by manufacturing a wall-like structure from which three different specimen types were obtained: specimens in which the loading direction was the same as the printing direction (vertical), specimens in which these two directions were perpendicular (horizontal), and bimetallic specimens in which the interface between the AISI 1045 substrate and the 18Ni300 steel was tested. The yield strength of the produced samples was 987.9±34.2, 925.9±89.7 and 486.7±47.2MPa for the vertical, horizontal and bimetallic specimens, respectively, while the elongation to failure was 9.4±1.9, 18.3±2.3 and 14.06±0.6% in the same order. The latter specimen failed within the substrate-comprised portion of the specimen. Additionally, the fracture surfaces were analysed through scanning electron microscopy, concluding that while both surfaces consist of dimples, the horizontal specimen presented microporosities with a reduced diameter. A microhardness analysis in the printed wall-like structure following the printing direction yielded an average hardness of 392±21 HV0.3, with fluctuations along the build direction mostly within one standard deviation.

In this article, a finite element (FE) thermal–electrical model with a trunk-conical discharge channel is employed to simulate individual EDM discharges with a time-on of 18 μs up to 320 μs, which are subsequently compared with the experimental results to validate the model. The discharge channel is a trunk-conical electrical conductor which dissipates heat by the Joule heating effect, being the correspondent factor equal to 1. Instead of the usual copper–iron electrode combination, steel (DIN CK45) and aluminium alloys (DIN 3.4365) are the implemented materials on both the tool and the workpiece, respectively. The numerical results were measured using the melting temperature of the materials as the boundary of material removal. The results obtained with the thermal–electrical model, namely the tool wear ratio, the tool wear rate, the material removal rate, and the surface roughness, are in good agreement with experimental results, showing that the new FE model is capable of predicting accurately with different materials for the electrodes.