Open Access
Development of a machining strategy to manufacture SiSiC nuts by EDM
(SAGE Publications, 2024) Torres Salcedo, Alexia; Puertas Arbizu, Ignacio; Luis Pérez, Carmelo Javier; Ingeniería; Ingeniaritza
Today, the high-precision manufacturing of small cavities in difficult-to-machine materials is still a challenge, even more so if they need to be threaded. The machining time, the wear suffered by the electrodes and the surface finish are determining factors in the efficiency of the threading process. However, there is scant literature on this subject so there is a need to study the process and the parameters involved. Thus, this study presents a novel machining strategy for the manufacture of nuts using die-sinking electrical discharge machining (EDM). Moreover, the novelty of this strategy is that it is carried out in a single stage and with a conventional EDM generator. To do so, a design of experiments (DOE) methodology has been followed. First, the optimal machining conditions are determined by studying the influence of EDM parameters on operation variables and mathematical models are developed using multiple linear regression. These models allow the behavior of the response variables under study to be predicted. Finally, this machining strategy developed from the previous experimental results is validated in the manufacturing process of a final part, specifically a square nut. It can be concluded that the mathematical model is good enough to predict the experimental results. Thus, the new method presented and described in this present study allowed a nut to be obtained with a real arithmetic mean deviation of the roughness profile (Ra) value of 1.27 μm whereas the predicted value from the model was 1.28 μm. To do so, the machining conditions selected were: 4 A (current intensity), 5 µs (pulse time) and 0.4 (duty cycle), which also gave a material removal rate (MRR) value of 0.5370 mm3/min. The machining strategy proposed here may be used for future research works related to the manufacturing of mechanical joints made of conductive ceramic materials.
Open Access
Filtro de material cerámico electroconductor
(2024) Luis Pérez, Carmelo Javier; Puertas Arbizu, Ignacio; Torres Salcedo, Alexia; Ingeniería; Ingeniaritza
La presente invención se refiere al desarrollo de componentes con cuerpos de materiales cerámicos conductores que presenten orificios pasantes y/o ranuras pasantes para su posterior aplicación como elementos de filtrado, mediante el empleo de procesos de electroerosión por penetración. Entre dichos materiales cerámicos se pueden citar: carburo de silicio infiltrado con silicio (SiSiC), carburo de boro (B{sub,4}C) y diboruro de titanio (TiB{sub,2}), entre otros. Por ello, mediante la presente invención, es posible disponer de componentes para aplicaciones de filtrado con las propiedades inherentes a los materiales cerámicos junto con la gran variedad de formas, precisión dimensional y buen acabado superficial que es posible obtener mediante los procesos de electroerosión. Una de sus aplicaciones de filtrado más destacables sería la fabricación de filtros resistentes a alta temperatura con geometría cilíndrica para el filtrado de líquidos altamente corrosivos e impurezas.
Open Access
EDM machinability and surface roughness analysis of INCONEL 600 using graphite electrodes
(Springer, 2016) Torres Salcedo, Alexia; Puertas Arbizu, Ignacio; Luis Pérez, Carmelo Javier; Ingeniería; Ingeniaritza
Open Access
Surface roughness analysis on the dry turning of an Al-Cu alloy
(Elsevier, 2015) Torres Salcedo, Alexia; Puertas Arbizu, Ignacio; Luis Pérez, Carmelo Javier; Ingeniería Mecánica, Energética y de Materiales; Mekanika, Energetika eta Materialen Ingeniaritza
Nowadays, surface finish has become an important indicator of quality and precision in manufacturing processes and it is considered one of the most important parameter in Industry. In this present study, the influence of different machining parameters on surface roughness has been analyzed. All these parameters have been studied in terms of depth of cut (ap), feed rate (F), cutting speed (Vc) and tool radius (R). A 2030-T4 aluminium alloy has been selected. Moreover, Design of Experiments (DOE) techniques have been used to predict the surface quality in advance and to select the optimal turning conditions. The experimental results revealed that for dry turning operations and for the amplitude parameters, the most significant factor was the interaction effect between the depth of cut and the feed rate. In addition, for facing operations, the feed rate turned out to be the most statistically influential factor of all the surface roughness parameters.
Open Access
Análisis y modelización de los parámetros de influencia en la electroerosión por penetración de materiales de baja mecanizabilidad
(2016) Torres Salcedo, Alexia; Puertas Arbizu, Ignacio; Luis Pérez, Carmelo Javier; Ingeniería Mecánica, Energética y de Materiales; Mekanika, Energetika eta Materialen Ingeniaritza
En la presente tesis doctoral se realiza un análisis y una modelización de los parámetros de mayor influencia en la electroerosión por penetración de tres materiales de baja mecanizabilidad. En concreto, el estudio se centra en la aleación Inconel® 600 (Special Metals Corporation) y en las cerámicas diboruro de titanio (TiB2) y carburo de silicio infiltrado con silicio (SiSiC). Actualmente, estos materiales resultan de gran interés para aplicaciones industriales en los sectores aeronáutico, nuclear y automotriz, debido a la combinación de buenas propiedades mecánicas, resistencia a la corrosión y extremada dureza a altas temperaturas. Para llevar a cabo dicho estudio, se emplean metodologías basadas en el Diseño de Experimentos (DOE), para la planificación y selección de los valores de los parámetros, así como para la obtención de modelos matemáticos que permitan predecir las condiciones óptimas de mecanizado. Asimismo, se determinan tablas tecnológicas, para dichos materiales, en función de los parámetros de diseño: intensidad, tiempo de impulso y rendimiento, en los rangos de estudio considerados. A partir de estas tablas, es posible predecir la obtención de una determinada rugosidad superficial en base a dos estrategias de mecanizado consistentes en maximizar la tasa de eliminación de material, o bien, en minimizar el desgaste del electrodo. Para la generación de las tablas tecnológicas, se emplean los valores experimentales y, en aquellos casos donde no sea posible disponer de datos experimentales, se emplean métodos de optimización no lineal para predecir dichos valores, utilizando los modelos matemáticos generados, en base a los resultados experimentales. Además, se hace uso de microscopía electrónica de barrido (SEM), con objeto de obtener información relativa a la topografía de las superficies resultantes tras la EDM. Finalmente, se propone un nuevo parámetro denominado ‘densidad de energía’ con el fin de profundizar en el estudio del proceso de EDM.
Open Access
Optimization and modeling of ZrB2 ceramic processing by EDM for high-performance industrial applications
(Elsevier, 2025-04-11) Luis Pérez, Carmelo Javier; Torres Salcedo, Alexia; Puertas Arbizu, Ignacio; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2
This study investigates the Electrical Discharge Machining (EDM) of zirconium diboride (ZrB2), a novel conductive ceramic with exceptional properties, including high temperature resistance, excellent thermal conductivity, and remarkable hardness. These properties make ZrB2 highly suitable for extreme environments, such as aerospace and nuclear applications. To the best of our knowledge, no comprehensive studies have addressed the manufacturing of ZrB2 parts by EDM, positioning this research as a cutting-edge contribution. Two electrode materials, graphite (C) and copper-graphite (Cu–C), were used to analyze the material removal rate (MRR) and surface roughness (Ra) as functions of current intensity (I), pulse time (ti), and duty cycle (η). Multiple Linear Regression (MLR) and Artificial Neural Networks (ANN) were used to model the response variables. While MLR was effective for MRR (R2 > 0.9), ANN outperformed it in predicting Ra, especially for Cu–C electrodes (R2 = 0.9366 vs. 0.3847 for MLR). Current intensity was the most influential parameter for MRR, while pulse time significantly affected Ra. Residual analysis confirmed ANN superior accuracy for Ra, with residuals below ±1 vs. ±2 for MLR. The study culminated in the successful EDM manufacture of a ZrB2 hexagonal nut, employing optimized parameters (I = 6 A, ti = 50 μs, η = 0.3, for the C electrode) derived using ANN models and particle swarm optimization. This result demonstrates the EDM process ability to produce high-precision components with complex geometries, showcasing its versatility and industrial potential. Therefore, this study broadens the understanding of ZrB2 machinability and expands its applications in advanced technologies.
Open Access
Study and optimization of the punching process of steel using the Johnson-Cook damage model
(MDPI, 2024) Claver Alba, Adrián; Hernández Acosta, Andrea; Barba Areso, Eneko; Fuertes Bonel, Juan Pablo; Torres Salcedo, Alexia; García Lorente, José Antonio; Luri Irigoyen, Rodrigo; Salcedo Pérez, Daniel; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2
Sheet metal forming processes are widely used in applications such as those in the automotive or aerospace industries. Among them, punching is of great interest due to its high productivity and low operating cost. However, it is necessary to optimize these processes and adjust their parameters, such as clearance, shear force or tool geometry, to obtain the best finishes and minimize crack generation. Thus, the main objective of this research work is to optimize the punching process to achieve parts that do not require subsequent processes, such as deburring, by controlling the properties of the starting materials and with the help of tools such as design of experiments and simulations. In the present study, tensile tests were performed on three steels with different compositions and three sample geometries. The information obtained from these tests has allowed us to determine the parameters of the Johnson-Cook damage criteria. Moreover, punching was performed on real parts and compared with simulations to analyze the percentage of burnish surface. The results obtained show that the methodology used was correct and that it can be extrapolated to other types of die-cutting processes by reducing the percentage of surface fractures and predicting the appearance of cracks. Furthermore, it was observed that clearance has a greater influence than processing speed, while the minimum percentage of the burnish area was observed for the minimum values of clearance.
Open Access
A study on the EDM drilling of reaction-bonded silicon carbide using different electrode materials
(Springer, 2023) Torres Salcedo, Alexia; Luis Pérez, Carmelo Javier; Puertas Arbizu, Ignacio; Corres Sanz, Jesús María; Ingeniería; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Today, there is a growing demand for efficient hole manufacturing technology in many industries such as aeronautics, automotive and nuclear, among others. Thus, the present study deals with the machining of through holes on SiSiC advanced ceramic by using Electrical Discharge Machining (EDM) drilling technology. Since recommendations related to the electrode characteristics and settings parameters are found to be scant for the industrial use of EDM drilling of SiSiC ceramics, this research work comes to cover this gap as it presents a complete study focused on the influence on different electrodes under rough and finish machining conditions. In particular, the influence of four electrodes materials (copper, copper-tungsten, graphite and copper infiltrated graphite) and three different electrode diameters ranging from 2 to 4 mm are investigated. In addition, the rotational speed of the electrode is also analysed. From the experimental results, both electrode material and machining regime, seem to be the most relevant factors of all. In the case of 2 mm diameter electrode, material removal rate (MRR) with Cu electrode was, approximately, 4.5 times higher than that obtained with a C electrode. In fact, it was found that copper electrode rotating at 20 rpm combined with high values of discharge energy (I = 2 A; ti = 70 µs) is the most economical option in terms of production cost and production time, as it gives a high MRR of 0.4754 mm3/min and a minimum electrode wear (EW) value of 7.52%. Moreover, slightly higher values of MRR were achieved for CuC electrode compared to those obtained with C electrode, indicating that the addition of Cu in the electrode contributes to a greater removal of material. However, a value of Ra of 0.37 µm could be obtained by setting low current intensity values (I = 0.5 A; ti = 45 µs) combined with C electrodes and with no rotation.
Open Access
Spacing roughness parameters analysis on the EDM of Inconel (R) 600 alloy
(Elsevier, 2017) Torres Salcedo, Alexia; Puertas Arbizu, Ignacio; Luis Pérez, Carmelo Javier; Ingeniería Mecánica, Energética y de Materiales; Mekanika, Energetika eta Materialen Ingeniaritza
Many research studies may be found regarding the measurement of surface roughness parameters. Most of them are focused on amplitude parameters as they are the most commonly used in industry, while little research has been found on the spacing ones. Spacing roughness parameters measure the horizontal characteristics of the surface deviations. In this present study, the influence of current intensity, pulse time and duty cycle on spacing roughness parameters Sm and Pc has been analyzed. Design of experiments techniques are used in order to both model and predict the most influential factors by using a small number of experiments. Current intensity of 2 A, pulse time of 25 mu s and duty cycle of 0.5 are selected as the best machining conditions in order to obtain the lowest surface roughness.
Open Access
Analytical modelling of energy density and optimization of the EDM machining parameters of Inconel 600
(MDPI, 2017) Torres Salcedo, Alexia; Puertas Arbizu, Ignacio; Luis Pérez, Carmelo Javier; Ingeniería Mecánica, Energética y de Materiales; Mekanika, Energetika eta Materialen Ingeniaritza
In this present research work, a new modelling of energy density in EDM (Electrical Discharge Machining) is proposed. Energy density can be defined as the amount of energy needed to get a unit volume of material removed, and for its modelling, the whole EDM process has been taken into account. This new definition lets us quantify the energy density that is being absorbed by the workpiece and the electrode. Results are compared to those obtained by die sinking EDM in an Inconel ®600 alloy using Cu-C electrodes. Currently, this material is of great interest for industrial applications in the nuclear, aeronautical and chemical sectors, due to their combinations of good mechanical properties, corrosion resistance and extreme hardness at very high temperatures. The experimental results confirm that the use of negative polarity leads to a higher material removal rate, higher electrode wear and higher surface roughness. Moreover, the optimal condition to obtain a maximum MRR (Material Removal Rate) of 30.49 mm3/min was: 8 A, 100 µs and 0.6, respectively, for the current intensity, pulse time and duty cycle.