Open Access
On the application of a design of experiments along with an anfis and a desirability function to model response variables
(MDPI, 2021) Luis Pérez, Carmelo Javier; Ingeniería; Ingeniaritza
In manufacturing engineering, it is common to use both symmetrical and asymmetrical factorial designs along with regression techniques to model technological response variables, since the in-advance prediction of their behavior is of great importance to determine the levels of variation that lead to optimal response values to be obtained. For this purpose, regression techniques based on the response surface method combined with a desirability function for multi-objective optimization are commonly employed, since it is usual to find manufacturing processes that require simultaneous optimization of several variables, which exhibit in many cases an opposite behavior. However, these regression models are sometimes not accurate enough to predict the behavior of these response variables, especially when they have significant non-linearities. To deal with this drawback, soft computing techniques are very effective in overcoming the limitations of conventional regression models. This present study is focused on the employment of a symmetrical design of experiments along with a new desirability function, which is proposed in this study, and with soft computing techniques based on fuzzy logic. It will be shown that more accurate results than those obtained from regression techniques are obtained. Moreover, this new desirability function is analyzed in this study.
Open Access
Elemento de refrigeración de material cerámico electroconductor
(2024) Luis Pérez, Carmelo Javier; Puertas Arbizu, Ignacio; Torres Salcedo, Alexia; Ingeniería; Ingeniaritza
Elemento de refrigeración de material cerámico electroconductor que comprende un cuerpo (1) con al menos un orificio (2) pasante y/o al menos una ranura (3) pasante, configurados para el paso de un fluido de refrigeración, donde al menos un orificio (2) y/o la al menos una ranura (3) están fabricados mediante electroerosión por penetración sobre el cuerpo (1) de material cerámico electroconductor.
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
Analysis of tribological properties in disks of AA-5754 and AA-5083 aluminium alloys previously processed by equal channel angular pressing and isothermally forged
(MDPI, 2020) Luis Pérez, Carmelo Javier; Luri Irigoyen, Rodrigo; Puertas Arbizu, Ignacio; Salcedo Pérez, Daniel; León Iriarte, Javier; Fuertes Bonel, Juan Pablo; Ingeniería; Ingeniaritza
In the present study, the wear behaviour of two aluminium alloys (AA‐5754 and AA‐5083) is analysed where these have been previously processed by severe plastic deformation (SPD) with equal channel angular pressing (ECAP). In order to achieve the objectives of this study, several disks made of these alloys are manufactured by isothermal forging from different initial states. The microstructures of the initial materials analysed in this study have different accumulated deformation levels. In order to compare the properties of the nanostructured materials with those which have not been ECAP‐processed, several disks with a height of 6 mm and a diameter of 35 mm are manufactured from both aluminium alloys (that is, AA‐5754 and AA‐5083) isothermally forged at temperatures of 150 and 200 °C, respectively. These thus‐manufactured disks are tested under a load of 0.6 kN, which is equivalent to a stress mean value of 18 MPa, and at a rotational speed of 200 rpm. In order to determine the wear values, the disks are weighed at the beginning, at 10,000 revolutions, at 50,000 revolutions and at 100,000 revolutions, and then the volume‐loss values are calculated. This study was carried out using specific equipment, which may be considered to have a block‐on‐ring configuration, developed for testing in‐service wear behaviour of mechanical components. From this, the wear coefficients for the two materials at different initial states are obtained. In addition, a comparison is made between the behaviour of the previously ECAP-processed aluminium alloys and those that are non‐ECAP‐processed. A methodology is proposed to determine wear coefficients for the aluminium alloys under consideration, which may be used to predict the wear behaviour. It is demonstrated that AA‐5754 and AA‐5083 aluminium alloys improve wear behaviour after the ECAP process compared to that obtained in non‐ECAP‐processed materials.
Open Access
Analysis of AM parameters on surface roughness obtained in PLA parts printed with FFF technology
(MDPI, 2021) Buj Corral, Irene; Sánchez Casas, Xabier; Luis Pérez, Carmelo Javier; Ingeniería; Ingeniaritza
Fused filament fabrication (FFF) 3D printing technology allows very complex parts to be obtained at a relatively low cost and in reduced manufacturing times. In the present work, the effect of main 3D printing parameters on roughness obtained in curved surfaces is addressed. Polylactic acid (PLA) hemispherical cups were printed with a shape similar to that of the acetabular part of the hip prostheses. Different experiments were performed according to a factorial design of experiments, with nozzle diameter, temperature, layer height, print speed and extrusion multiplier as variables. Different roughness parameters were measured—Ra, Rz, Rku, Rsk—both on the outer surface and on the inner surface of the parts. Arithmetical mean roughness value Ra and greatest height of the roughness profile Rz are usually employed to compare the surface finish among different manufacturing processes. However, they do not provide information about the shape of the roughness profile. For this purpose, in the present work kurtosis Rku and skewness Rsk were used. If the height distribution in a roughness profile follows a normal law, the Rku parameter will take a value of 3. If the profile distribution is symmetrical, the Rsk parameter will take a value of 0. Adaptive neural fuzzy inference system (ANFIS) models were obtained for each response. Such models are often employed to model different manufacturing processes, but their use has not yet been extended to 3D printing processes. All roughness parameters studied depended mainly on layer height, followed by nozzle diameter. In the present work, as a general trend, Rsk was close to but lower than 0, while Rku was slightly lower than 3. This corresponds to slightly higher valleys than peaks, with a rounded height distribution to some degree.
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
Modeling of surface roughness in honing processes by using fuzzy artificial neural networks
(MDPI, 2023) Buj Corral, Irene; Sender, Piotr; Luis Pérez, Carmelo Javier; Ingeniería; Ingeniaritza
Honing processes are abrasive machining processes which are commonly employed to improve the surface of manufactured parts such as hydraulic or combustion engine cylinders. These processes can be employed to obtain a cross-hatched pattern on the internal surfaces of cylinders. In this present study, fuzzy artificial neural networks are employed for modeling surface roughness parameters obtained in finishing honing operations. As a general trend, main factors influencing roughness parameters are grain size and pressure. Mean spacing between profile peaks at the mean line parameter, on the contrary, depends mainly on tangential and linear velocity. Grain Size of 30 and pressure of 600 N/cm2 lead to the highest values of core roughness (Rk) and reduced valley depth (Rvk), which were 1.741 µm and 0.884 µm, respectively. On the other hand, the maximum peak-to-valley roughness parameter (Rz) so obtained was 4.44 µm, which is close to the maximum value of 4.47 µm. On the other hand, values of the grain size equal to 14 and density equal to 20, along with pressure 600 N/cm2 and both tangential and linear speed of 20 m/min and 40 m/min, respectively, lead to the minimum values of core roughness, reduced peak height (Rpk), reduced valley depth and maximum peak-to-valley height of the profile within a sampling length, which were, respectively, 0.141 µm, 0.065 µm, 0.142 µm, and 0.584 µm.
Open Access
Experimental and FEM analysis of wear behaviour in AA5083 ultrafine-grained cams
(MDPI, 2020) Luis Pérez, Carmelo Javier; Luri Irigoyen, Rodrigo; Fuertes Bonel, Juan Pablo; León Iriarte, Javier; Salcedo Pérez, Daniel; Puertas Arbizu, Ignacio; Ingeniería; Ingeniaritza
Severe plastic deformation (SPD) processes have attracted a great deal of both scientific and technological interest over the last few years as a consequence of the improvements that are possible to obtain in the microstructure and mechanical properties of the materials manufactured through the use of these kind of processes. However, the practical applications of such materials to obtain mechanical components are significantly fewer. As a direct consequence, the same thing has been observed in the development of studies that show the in-service behaviour of the mechanical components developed in this way. Since one of the industrial objectives of these SPD processes is to obtain functional parts, it is necessary to carry out studies to fill this gap. Therefore, in this study, an analysis of the wear that cams undergo when manufactured from an AA5083 aluminium-magnesium alloy is carried out. The cams were isothermally-forged from materials with and without previous SPD processing by equal channel angular pressing (ECAP). Subsequently, the wear behaviour of these cams was analysed by using specific equipment, which may have been considered to have a block-on-ring configuration, developed for testing in-service wear behaviour of mechanical parts. From this comparative wear study with cams, it is shown that previously-processed materials by ECAP have a better wear performance. Moreover, finite element modelling (FEM) simulations were also included to predict wear in the cams processed in this way. A good agreement between FEM and experimental results was obtained. It is this aspect of performing the wear tests on functional and real mechanical components, and not on laboratory samples, which makes this present research work novel.
Open Access
Study of the industrial application of diamond-like carbon coatings deposited on advanced tool steels
(MDPI, 2024) Barba Areso, Eneko; Claver Alba, Adrián; Montalá, Francesc; Luis Pérez, Carmelo Javier; Sala, Neus; Colominas, Carles; García Lorente, José Antonio; Ingeniería; Ingeniaritza
The utilization of diamond-like carbon (DLC) coatings has emerged as a promising strategy to enhance the performance, durability, and functionality of industrial tools and components. Recognized for their exceptional attributes such as hardness, wear resistance, low friction, and biocompatibility, DLC coatings have achieved widespread acclaim for their potential to improve the capabilities of tool steels for different applications. This present study shows a comprehensive investigation into the application of DLC coatings on a diverse range of tool steel substrates, encompassing 1.2379, 1.2358, Caldie, K340, HWS, and Vanadis 4. The main aim is to show the effects of DLC coatings on these substrates and to provide an in-depth analysis of their properties during forming processes. Furthermore, this study explores the practical utilization of DLC-coated tool steel components, with a particular focus on their role in cold forming dies. Additionally, the study reviews the application of duplex treatments involving plasma nitriding to enhance DLC coating performance. To sum up, this study pursues a threefold objective: to investigate DLC coatings’ performance on diverse tool steel substrates; to assess the potential for improvement through nitriding; and to evaluate the behavior of DLC coatings in the cold stamping of S235 steel, which is of great technological and industrial interest to the cold forging sector.
Open Access
Using a fuzzy inference system to obtain technological tables for electrical discharge machining processes
(MDPI, 2020) Luis Pérez, Carmelo Javier; Ingeniería; Ingeniaritza
Technological tables are very important in electrical discharge machining to determine optimal operating conditions for process variables, such as material removal rate or electrode wear. Their determination is of great industrial importance and their experimental determination is very important because they allow the most appropriate operating conditions to be selected beforehand. These technological tables are usually employed for electrical discharge machining of steel, but their number is significantly less in the case of other materials. In this present research study, a methodology based on using a fuzzy inference system to obtain these technological tables is shown with the aim of being able to select the most appropriate manufacturing conditions in advance. In addition, a study of the results obtained using a fuzzy inference system for modeling the behavior of electrical discharge machining parameters is shown. These results are compared to those obtained from response surface methodology. Furthermore, it is demonstrated that the fuzzy system can provide a high degree of precision and, therefore, it can be used to determine the influence of these machining parameters on technological variables, such as roughness, electrode wear, or material removal rate, more efficiently than other techniques.