The 3D printing process offers several advantages to the medical industry by producing complex and bespoke devices that accurately reproduce customized patient geometries. Despite the recent developments that strongly enhanced the dominance of additive manufacturing (AM) techniques over conventional methods, processes need to be continually optimized and controlled to obtain implants that can fulfill all the requirements of the surgical procedure and the anatomical district of interest. The best outcomes of an implant derive from optimal compromise and balance between a good interaction with the surrounding tissue through cell attachment and reduced inflammatory response mainly caused by a weak interface with the native tissue or bacteria colonization of the implant surface. For these reasons, the chemical, morphological, and mechanical properties of a device need to be designed in order to assure the best performances considering the in vivo environment components. In particular, complex 3D geometries can be produced with high dimensional accuracy but inadequate surface properties due to the layer manufacturing process that always entails the use of post-processing techniques to improve the surface quality, increasing the lead times of the whole process despite the reduction of the supply chain. The goal of this work was to provide a comparison between Ti6Al4V samples fabricated by selective laser melting (SLM) and electron beam melting (EBM) with different building directions in relation to the building plate. The results highlighted the influence of the process technique on osteoblast attachment and mineralization compared with the building orientation that showed a limited effect in promoting a proper osseointegration over a long-term period.

Micro milling process of CuZn37 brass is considered important due to applications in tool production for micro moulding and micro replication technology. The variations in material properties, work material adhesion to tool surfaces, burr formation, and tool wear result in loss of productivity. The deformed chip shapes together with localized temperature, plastic strain, and cutting forces during micro milling process can be predicted using finite element (FE) modeling and simulation. However, toolworkpiece engagement suffers from tool run-out affecting process performance in surface generation. This work provides experimental investigations on effects of tool run-out as well as process insight obtained from simulation of chip flow, with and without considering tool run-out. Scanning electron microscope (SEM) observation of the 3D chip shapes demonstrates ductile deformed surfaces together with localized serration behavior. FE simulations are utilized to investigate the effects of micro milling operation, cutting speed, and feed rate on forces, chip flow, and shapes. Predicted cutting forces and chip flow results from simulations are compared with force measurements, tool run-out, and chip morphology revealing reasonable agreements.

In recent years, miniaturization of components has been concerned with several industrial fields including aerospace, energy, and electronics. This phenomenon resulted in increasing demand of micro-components with complex shape and high strength, often in high-temperature environment. Nickel-based superalloys such as Inconel 625 are a class of material suitable to aforementioned applications and can be successfully processed with Additive Manufacturing (AM). Moreover, micro-milling can be employed to manufacture micro-scale features on the additively fabricated parts or to achieve better surface finishes, as required for high-precision mechanical assemblies. In micro machining, it is possible to notice a lack of scientific study focusses on the material removal behavior of difficulty-to-cut alloys produced via Additive Manufacturing. This paper describes an analytical cutting force model suitable also for AM'd parts which considers the presence of ploughing-and shearing-dominated cutting regimes. A refinement procedure of the cutting force model was defined and applied by performing an experimental work on Inconel 625 samples fabricated by LaserCUSING™. A search algorithm was employed to develop an iterative methodology to determine the unknown cutting force model parameters. The model was successfully utilized to predict how the cutting force is affected as the process parameters change.

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