Additive manufacturing technologies play an important role in Industry 4.0. One of the most prevalent processes is fused deposition modelling (FDM) due to its versatility and low cost. However, there is still a lack of standardization of materials and procedures within this technology. This work aims to study the relationship of certain operating parameters and the conditions of poly(lactic acid) (PLA) polymer with the results of the manufactured parts in dimensional terms, surface quality, and mechanical strength. In this way, the impact of some material characteristics is analyzed, such as the pigmentation of the material and the environmental humidity where it has been stored. The manufacturing parameter that relates to these properties has been the extrusion temperature since it is the most influential in this technology. The results are quite affected especially by humidity, being a parameter little studied in the literature.

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The application of techniques to improve the surface finish of pieces obtained by fused deposition modelling, as well as other functional aspects, is of great interest nowadays. Polylactic acid, a biodegradable material, has been considered a possible substitute for petroleum-based polymers. In this work, different chemical post-processing methods are applied to polylactic acid pieces obtained by fused deposition modelling and some characteristics are studied. Structural, thermal, and crystallinity property changes are analyzed according to the treatments applied. This can prevent degradation, eliminate the glass transition phase of the material, and thereby increase the thermal resistance by about 50 °C. An improvement in the roughness of the pieces of up to 97% was also found.

One of the main criteria for the establishment of the performance of a forming process by material removal is based on cutting tool wear. Wear is usually caused by different mechanisms, however, only one is usually considered as predominant or the controller of the process. This experimental research is focused on the application of Pin-on-Disc wear tests, in which the tribological interference between UNS A92024-T3 Aluminum–Copper alloy and tungsten carbide (WC–Co) has been studied. The main objective of this study is focused on the determination of the predominant wear mechanisms involved in the process, as well as the characterization of the sliding and friction effects by using SEM and Energy Dispersion Spectroscopy (EDS) techniques, as applied to WC–Co (cutting tool material)/Al (workpiece material) which are widely used in the aerospace industry. Performed analysis prove the appearance of abrasive wear mechanisms prior to adhesion. This fact promotes adhesion mechanisms in several stages because of the surface quality deterioration, presenting different alloy composition in the form of a Built-Up Layer (BUL)/Built-Up Edge (BUE).

This work reports on the results of a study of different macro-geometrical deviation parameters, such as Straightness (SD), Parallelism (PD) and Circularity (CD) as a function of cutting speed (v) and feed (f) of dry turned UNS A92024 (Al-Cu) cylindrical bars. The results obtained have allowed establishing exponentials parametric model for predicting these deviations as a function of those cutting parameters. As a consequence of that, geometrical surfaces SD(f,v), PD(f,v) and CD(f,v) have been developed for this alloy. These surfaces allows determining marginal curves for specific v and f values, respectively, out the parameter ranges employed. So, macro-geometrical deviations can be predicted through this model for v and f values out of those considered in the study for each alloys.

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Adhesion wear is the main wear mechanism in the dry turning of aluminium alloys. This type of wear produces an adhesion of the machining material on the cutting tool, decreasing the final surface quality of the machining parts and making it more difficult to maintain industrial tolerances. This work studies the influence of the cutting parameters on the volume of material adhered to the cutting tool surface for dry machining of AA2024 (Al-Cu). For that purpose, a specific methodology based on the automatic image processing method that can obtain the area and the thickness of the adhered material has been designed. This methodology has been verified with the results obtained through 3D analysis techniques and compared with the adhered volume. The results provided experimental parametric models for this wear mechanism. These models are analytic approximations of experimental data. The feed rate mainly results in low cutting speed, while low depths of cut presents a different behaviour due to the low contact pressure. The unstable behaviour of aluminium adhesion on the cutting tool produces a high variability of results. This continuous change introduces variation in the process caused by the continuous change of the cutting tool geometry.