Persona: Rubio Alvir, Eva María
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erubio@ind.uned.es
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0000-0001-8385-3540
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Rubio Alvir
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Eva María
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Publicación Experimental study of magnesium drilling based on the surface quality(Elsevier, 2019) Berzosa, Fernando; Agustina Tejerizo, Beatriz De; Rubio Alvir, Eva María; Marín Martín, Marta MaríaNowadays, the use of magnesium and its alloys for transport applications is based on the combination of high mechanical properties and low density. In general, the machinability of these materials is considered to be good. Nevertheless, it has been reported that the machining of these alloys involves some critical problems regarding their tendency to be flammable at high temperatures and consequently, there is a risk of chip ignition in the working area during the process. This fact is especially critical when the size of chips is reduced. In this study, the influence of cutting conditions on surface roughness, in terms of Ra, obtained by drilling of magnesium alloy (AZ91D-F) was carried out. A factorial design 2 4 was employed for the planning of the drilling tests. The factors considered were the feed rate (0.05 and 0.2 mm/r), cutting speed, 40 and 60 m/min, the type of tool, in particular, the point angle of 118º and 135º, and the cooling system, Dry conditions and MQL (Minimum Quantity Lubrication) system. As main conclusions it can be affirmed that improved surface roughness is obtained with the cutting conditions selected in this study. Furthermore, at 0.05 mm/r and 40 m/min the use of tools with a point angle of 135º provides lower values of Ra than the tool of 118º point angle. Slightly lower values of Ra are obtained with tools of 118º point angle at 0.2 mm/r and 60 m/min.Publicación Experimental Study for Improving the Repair of Magnesium–Aluminium Hybrid Parts by Turning Processes(MDPI, 2018-01-16) Rubio Alvir, Eva María; Villeta, María; Valencia, José Luis; Sáenz de Pipaón, José Manuel; MDPIOne of the lightest metallic materials used in the aeronautics, aerospace, and automotive industries, among others, is magnesium, due to its excellent weight/strength ratio. Most parts used in these industries need to be made of materials that are rigid, strong, and lightweight, but sometimes the materials do not simultaneously satisfy all of the properties required. An alternative is to combine two or more materials, giving rise to a hybrid component that can satisfy a wider range of properties. The pieces machined in these industrial fields must satisfy stringent surface roughness requirements that conform to the design specifications. This work shows an experimental study to analyse the surface roughness reached in hybrid components made up of a base of magnesium alloy (UNS M11917) and two inserts of aluminium alloy (UNS A92024) obtained by turning. Its purpose is to determine the influence of the factors and their possible interactions on the response variable, the surface roughness Ra. The study is carried out using a design of experiments (DOE). A product of a full factorial 23 and a block of two factors 3 2 was selected. The factors identified as possible sources of variation of the surface roughness are: depth of cut, feed rate, spindle speed, type of tool, location with respect to the specimen (LRS), and location with respect to the insert (LRI). Data were analysed by means of the analysis of variance (ANOVA) method. The main conclusion is the possibility to carry out the repair and maintenance of parts of magnesium–aluminum hybrid components by dry turning; that is, without cutting fluids and, therefore, in the most sustainable way that the process can be carried out. In addition, different combinations of cutting parameters have been identified that allow these operations to be carried out in an efficient manner, reducing mechanization times and, therefore, also the direct and indirect costs associated with them.Publicación Surface Roughness Evaluation Based on Acoustic Emission Signals in Robot Assisted Polishing(MDPI, 2014-11-14) Agustina Tejerizo, Beatriz De; Marín Martín, Marta María; Teti, Roberto; Rubio Alvir, Eva María; MDPIThe polishing process is the most common technology used in applications where a high level of surface quality is demanded. The automation of polishing processes is especially difficult due to the high level of skill and dexterity that is required. Much of this difficulty arises because of the lack of reliable data on the effect of the polishing parameters on the resulting surface roughness. An experimental study was developed to evaluate the surface roughness obtained during Robot Assisted Polishing processes by the analysis of acoustic emission signals in the frequency domain. The aim is to find out a trend of a feature or features calculated from the acoustic emission signals detected along the process. Such an evaluation was made with the objective of collecting valuable information for the establishment of the end point detection of polishing process. As a main conclusion, it can be affirmed that acoustic emission (AE) signals can be considered useful to monitor the polishing process state.Publicación Thicknesses/Roughness Relationship in Mg-Al-Mg and Mg-Ti-Mg Hybrid Component Plates for Drilled Aeronautical Lightweight Parts(MDPI, 2020-11-19) Blanco, David; Rubio Alvir, Eva María; Sáenz de Pipaón, José Manuel; Marín Martín, Marta María; MDPI; https://orcid.org/0000-0002-3776-5010Multimaterial hybrid compounds formed from lightweight structural materials have been acquiring great importance in recent years in the aeronautical and automotive sectors, where they are replacing traditional materials to reduce the mass of vehicles; this will enable either an increase in the action ratio or a reduction in the fuel consumption of vehicles and, in short, will lead to savings in transport costs and a reduction in polluting emissions. Besides, the implementation of production and consumption models based on the circular economy is becoming more and more important, where the repair and, for this purpose, the use of recyclable materials, is crucial. In this context, the analysis of a repair process is carried out by re-drilling Mg-Al-Mg multimaterial components using experimental design (DoE) based on Taguchi methodology, an analysis of variance (ANOVA) and descriptive statistics. The study concludes which are the significant factors and interactions of the process, comparing the results with previous similar studies, and establishing bases to determine the optimum thicknesses of hybrid magnesium-based component plates of drilled parts in the aeronautical industry, guaranteeing surface roughness requirements in repair and maintenance operations throughout their lifetime.Publicación Evolution and Latest Trends in Cooling and Lubrication Techniques for Sustainable Machining: A Systematic Review(MDPI, 2025-02-05) Polo, Samuel; Rubio Alvir, Eva María; Marín Martín, Marta María; Sáenz de Pipaón, José Manuel; MDPIThis document presents a review on cooling and lubrication methods in machining. A systematic search of information related to these methods was carried out based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) methodology. The importance of the sustainability of machining processes is highlighted, as they represent between 10 and 17% of the total manufacturing cost of the final part and have negative environmental and health impacts. Although dry machining completely eliminates the use of cutting fluids, in many cases it produces unsatisfactory results due to the increase in temperature inside the tool, which requires prior analysis to ensure its viability compared to conventional techniques. On the other hand, semi-dry machining, which significantly reduces the volume of cutting fluids, is a more competitive alternative, with results similar to those of conventional machining. Other sustainable cooling and lubrication methods are also being investigated, such as cryogenic and high-pressure cooling, which offer better machining results than conventional processes. However, they have a high initial cost and further research is needed to integrate them into industry. While the combination of these cooling and lubrication methods could lead to improved results, there is a notable lack of comprehensive studies on the subject.Publicación Sustainable Processes in Aluminium, Magnesium, and Titanium Alloys Applied to the Transport Sector: A Review(MDPI, 2021-12-22) Blanco, David; Lorente Pedreille, Raquel María; Saéz Nuño, María Ana; Rubio Alvir, Eva MaríaThe reduction of consumption and pollutant emissions is a top priority for the transport sector. One working line is the substitution of conventional structural materials with lightweight materials such as metallic alloys of aluminium, titanium, and/or magnesium. For this reason, and considering that the number of related articles is lower than the existing number of other structural lightweight materials, it is considered very convenient and helpful to carry out a systematic analysis of their latest trends through Open Access literature. A methodology adapted from the PRISMA statement is applied, in order to guarantee unbiasedness and quality in selecting literature and research. The final selection is made up of the 40 most cited research papers from 2015–2020, with an average of 20.6 citations per article. Turning and drilling are the most trending machining processes, and there is particular interest in the study of sustainable cooling, such as dry machining, cryogenic cooling, and MQL. In addition, another trending topic is multi-materials and joining dissimilar materials with guarantees. Additive manufacturing has also been identified as an increasingly trending theme, appearing in 18% of the selected studies. This work is complemented with summary tables of the most cited Open Access articles on sustainable machining and cooling, multi-materials or hybrid components, and additive manufacturing.Publicación Guidelines for Selecting Plugs Used in Thin-Walled Tube Drawing Processes of Metallic Alloys(MDPI, 2017-12-18) Rubio Alvir, Eva María; Camacho López, Ana María; Pérez, Rául; Marín Martín, Marta María; MDPIIn this paper, some practical guidelines to select the plug or set of plugs more adequate to carry out drawing processes of thin-walled tubes carried out with fixed conical inner plug are presented. For this purpose, the most relevant input parameters have been considered in this study: the tube material, the most important geometrical parameters of the process (die semiangle, a, and cross-sectional area reduction, r) and the friction conditions (Coulomb friction coefficients, m1, between the die and the tube outer surface, and m2, between the plug and the tube inner surface). Three work-hardening materials are analyzed: the annealed copper UNS C11000, the aluminum UNS A91100, and the stainless steel UNS S34000. The analysis is realized by means of the upper bound method (UBM), modelling the plastic deformation zone by triangular rigid zones (TRZ), under the validated assumption that the process occurs under plane strain conditions. The obtained results allow establishing, for each material, a group of geometrical parameters, friction conditions, a set of plugs that make possible to carry out the process under good conditions, and the optimum plug to carry out the process using the minimum amount of energy. The proposed model is validated by means of an own finite element analysis (FEA) carried out under different conditions and, in addition, by other finite element method (FEM) simulations and real experiments taken from other researchers found in the literature (called literature simulations and literature experimental results, respectively). As a main conclusion, it is possible to affirm that the plug that allows carrying out the process with minimum quantity of energy is cylindrical in most cases.Publicación Emerging Trends in Hybrid Additive and Subtractive Manufacturing(MDPI, 2025-05-29) Rabalo, Manuel Ángel; García Domínguez, Amabel; Rubio Alvir, Eva MaríaThe great capability of additive manufacturing to produce parts with complex, even impossible to achieve, geometries through five-or-more-axis machining or other conventional processes opened a promising future decades ago. For its part, mature subtractive manufacturing presents problems of material waste, especially relevant in the case of superalloys used in fields such as aerospace. From the need to overcome the limitations of both and take advantage of their capabilities, the new paradigm of hybrid additive and subtractive manufacturing was born, which today is defined as a hybrid flow of subprocesses that interact with the part in the same machine. This paper presents a review of the emerging trends in additive–subtractive manufacturing over the last five years. This review has been carried out by applying an adaptation of the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) methodology to the field of manufacturing engineering. Specifically, open access papers published in English between 2020 and 2024, collected in prestigious journals (classified as Q1 and Q2 within the ranking of their respective categories according to the Journal Citation Report), and peer-reviewed conference proceedings of recognized prestige have been selected. From the analysis of the selected articles, it is concluded that hybrid additive and subtractive manufacturing is especially focused on the aerospace field, using titanium and nickel alloys, combining processes among which DED (directed energy deposition) and milling stand out.Publicación Injection Mold for Plastics Manufactured by Metal-FFF with Conformal Cooling Channels: A Proof-of-Concept Case(MDPI, 2025-09-01) Solis, José Enrique; Claver Gil, Juan; Marín Martín, Marta María; Rubio Alvir, Eva María; García Domínguez, AmabelInjection molding is widely used for mass-producing plastic components, demanding precise thermal control to optimize cycle times and part quality. Traditional CNC-machined molds limit design flexibility and restrict advanced cooling features like conformal cooling channels (CCCs). Integrating CCCs improves cooling performance, reduces cycle times, and offers more efficient, cost-effective designs. Additive manufacturing (AM), especially Metal-Fused Filament Fabrication (Metal-FFF), offers geometries unattainable by machining. While most mold research focuses on Laser Powder Bed Fusion (LPBF), the feasibility of Metal-FFF molds remains underexplored. This study presents the design, fabrication, and experimental evaluation of an injection mold produced via Metal-FFF with integrated CCCs. The process included computational design, resistance simulations, fabrication, debinding, sintering, and post-processing, followed by testing under injection molding conditions. Results show that Metal-FFF molds with CCCs boost cooling efficiency, cutting cycle times by about 30% compared to conventional molds, while offering greater design freedom and economic benefits. Nonetheless, issues such as porosity and shrinkage need further refinement to fully leverage this technology for industrial use.Publicación Parametric Analysis of the Mandrel Geometrical Data in a Cold Expansion Process of Small Holes Drilled in Thick Plates(MDPI, 2019-12-08) Calaf-Chica, José; Marín Martín, Marta María; Rubio Alvir, Eva María; Teti, Roberto; Secreto, Tiziana; MDPICold expansion technology is a cold-forming process widely used in aeronautics to extend the fatigue life of riveted and bolted holes. During this process, an oversized mandrel is pushed through the hole in order to yield it and generate compressive residual stresses contributing to the fatigue life extension of the hole. In this paper, a parametric analysis of the mandrel geometrical data (inlet angle straight zone length and diametric interference) and their influence on the residual stresses was carried out using a finite element method (FEM). The obtained results were compared with the conclusions presented in a previous parametric FEM analysis on the influence of the swage geometry in a swaging cold-forming process of gun barrels. This process could be considered, in a simplified way, as a scale-up of the cold expansion process of small holes, and this investigation demonstrated the influence of the diameter ratio (K) on the relation between the mandrel or swage geometry and the residual stresses obtained after the cold-forming process.