Open Access
Weld joint reconstruction and classification algorithm for trajectory generation in robotic welding
(Trans Tech Publications, 2023) Curiel Braco, David; Veiga Suárez, Fernando; Suárez, Alfredo; Villanueva Roldán, Pedro; Aldalur, Eider; Ingeniería; Ingeniaritza
Open Access
Automatic trajectory determination in automated robotic welding considering weld joint symmetry
(MDPI, 2023) Curiel Braco, David; Veiga Suárez, Fernando; Suárez, Alfredo; Villanueva Roldán, Pedro; Aldalur, Eider; Ingeniería; Ingeniaritza
The field of inspection for welded structures is currently in a state of rapid transformation driven by a convergence of global technological, regulatory, and economic factors. This evolution is propelled by several key drivers, including the introduction of novel materials and welding processes, continuous advancements in inspection technologies, innovative approaches to weld acceptance code philosophy and certification procedures, growing demands for cost-effectiveness and production quality, and the imperative to extend the lifespan of aging structures. Foremost among the challenges faced by producers today is the imperative to meet customer demands, which entails addressing both their explicit and implicit needs. Furthermore, the integration of emerging materials and technologies necessitates the exploration of fresh solutions. These solutions aim to enhance inspection process efficiency while providing precise quantitative insights into defect identification and location. To this end, our project proposes cutting-edge technologies, some of which have yet to gain approval within the sector. Noteworthy among these innovations is the integration of vision systems into welding robots, among other solutions. This paper introduces a groundbreaking algorithm for tool path selection, leveraging profile scanning and the concept of joint symmetry. The application of symmetry principles for trajectory determination represents a pioneering approach within this expansive field.
Open Access
Cladding influence on the milling of low-stiffness aluminum alloy parts with local clamping
(Publicaciones DYNA, 2025-03-01) Casuso, Mikel; Rubio Mateos, Antonio; Silveira-Fernández, Elena; Veiga Suárez, Fernando; Lamikiz, Aitzol; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISC
The milling of aeronautical skins on flexible and reconfigurable fixtures is a major industrial challenge due both to the low rigidity of the skins and to the configuration of these fixtures, which, although they provide a great versatility of use and are an efficient alternative to pollutant chemical milling, vibrations can easily occur in them that may impair the surface quality, increase the error of the final thickness and cause excessive cutting forces. Aiming to foster the use of flexible fixtures, a study of the natural frequencies and cutting forces obtained when milling thin parts has been carried out, with special emphasis on analyzing the influence of the cladding of aluminum alloy parts.
Open Access
Three-dimensional finite element modelling of sheet metal forming for the manufacture of pipe components: symmetry considerations
(MDPI, 2022) Bhujangrao, Trunal; Veiga Suárez, Fernando; Penalva Oscoz, Mariluz; Costas, Adriana; Favieres Ruiz, Cristina; Ingeniería; Ingeniaritza
The manufacture of parts by metal forming is a widespread technique in sectors such as oil and gas and automotives. It is therefore important to make a research effort to know the correct set of parameters that allow the manufacture of correct parts. This paper presents a process analysis by means of the finite element model. The use case presented in this paper is that of a 3-m diameter pipe component with a thickness of 22 mm. In this type of application, poor selection of process conditions can result in parts that are out of tolerance, both in dimensions and shape. A 3D finite element model is made, and the symmetry of the tube section generated in 2D is analysed. As a novelty, an analysis of the process correction as a function of the symmetrical deformation of the material in this case in the form of a pipe is carried out. The results show a correct fitting of the model and give guidelines for manufacturing.
Open Access
Machine learning-based analysis engine to identify critical variables in multi-stage processes: application to the installation of blind fasteners
(DYNA, 2020) Murua Etxeberría, Maialen; Veiga Suárez, Fernando; Ortega Lalmolda, Juan Antonio; Penalva Oscoz, Mariluz; Díez Oliván, Alberto; Ingeniería; Ingeniaritza
Quality control in manufacturing is a recurrent topic as the ultimate goals are to produce high quality products with less cost. Mostly, the problems related to manufacturing processes are addressed focusing on the process itself putting aside other operations that belong to the part’s history. This research work presents a Machine Learning-based analysis engine for nonexpert users which identifies relationships among variables throughout the manufacturing line. The developed tool was used to analyze the installation of blind fasteners in aeronautical structures, with the aim of identifying critical variables for the quality of the installed fastener, throughout the fastening and drilling stages. The results provide evidence that drilling stage affects to the fastening, especially to the formed head’s diameter. Also, the most critical phase in fastening, which is when the plastic deformation occurs, was identified. The results also revealed that the chosen process parameters, thickness of the plate and the faster type influence on the quality of the installed fastener.
Open Access
High deposition wire arc additive manufacturing of mild steel: strategies and heat input effect on microstructure and mechanical properties
(Elsevier, 2020-09-02) Aldalur, Eider; Veiga Suárez, Fernando; Suárez, Alfredo; Bilbao, Jon; Lamikiz, Aitzol; Ingeniería; Ingeniaritza
Wire Arc Additive Manufacturing (WAAM) is a layer-by-layer production concept that is proposed as a promising alternative to traditional subtractive techniques due to its potential to manufacture large metallic components of medium geometrical complexity. In recent years, this technology has created interest due to the advantages it proposes, such as a low cost and high deposition rates in comparison with other Additive Manufacturing (AM) techniques. In this study, the Gas Metal Arc Welding (GMAW)-based WAAM system was developed to deposit mild steel material. To that end, a comprehensive methodology to understand the main process variables and their influence in the final component properties is shown. The aim of the present study was to compare the influence of oscillatory and overlapping deposition strategies in terms of productivity, growth per layer, obtained microstructure and mechanical properties using the control volume concept to compare volume-dependent parameters. Although some characteristics of these strategies have been documented in literature, the heat input influence has not yet been comprehensively demonstrated and understood. For example, heat input, analyzed deeply in the present study, is a critical factor for the stability of the WAAM process, influencing the mechanical properties and microstructural evolution of as-fabricated parts. The results indicate that the oscillated strategy increases productivity.
Open Access
Modeling of cutting force and final thickness for low stiffness 2024-T3 aluminum alloy part milling considering its geometry and fixtures
(Elsevier, 2022) Casuso, Mikel; Rubio Mateos, Antonio; Veiga Suárez, Fernando; Lamikiz, Aitzol; Ingeniería; Ingeniaritza
The aeronautic industry is facing many challenges regarding the lifetime, weight and accuracy that aircraft skins must comply to meet stringent structural and aerodynamic requirements. Currently, mechanical milling of aircraft skin parts of 2024-T3 aluminum alloy is displacing the highly pollutant chemical milling. Consequently, flexible and reconfigurable vacuum holding fixtures are being increasingly employed, because they are adaptable to several part geometries, but, since their rigidity is extremely reduced, the low stiffness of parts limits severely their deployment. Aiming to harness the full potential of these holding systems for aluminum alloy skin parts, a complete analysis of final thickness achieved and cutting force is developed. Thin floor parts of different geometries are pocket milled, simply screwed at their corners, emulating a skin part supported by four vacuum cups. Process forces are continuously monitored, and final thickness is measured. It has been proven that the reduction of mass and stiffness during milling causes a corresponding reduction of the natural frequencies of the parts. Also, as long as natural frequencies are not excited, final thickness error is almost constant and not affected by the tool position, but only by the initial geometry and fixtures distribution of the part. Additionally, a new cutting force model for skin parts is empirically calculated. Unlike models designed for fully supported parts, this model is designed for skins held in flexible fixtures. It has a relative error of 5.6% and it allows to optimize the trajectory, geometry and support distribution, thus boosting the use of flexible fixtures.
Open Access
Wire arc additive manufacturing of invar parts: bead geometry and melt pool monitoring
(Elsevier, 2022-02-15) Veiga Suárez, Fernando; Suárez, Alfredo; Aldalur, Eider; Artaza, Teresa; Ingeniería; Ingeniaritza
Additive manufacturing processes using the direct energy deposition method, one of which is the Wire Arc Additive Manufacturing (WAAM), have gained much attention in the scientific community over the last decade. The application of WAAM to Invar, an iron-nickel and manganese alloy, with a low amount of chromium carbon, also called FeNi36 or Nivarox has been the subject of various reports due to its challenging nature. This paper utilizes and unifies research material previously investigated in this technology, taking a new approach based on the study of symmetrical phenomena that guarantee the quality of the process. On the one hand, a method of analysis of the geometry of the manufactured wall is presented based on its symmetrical quality which guarantees the maximum use of material and, on the other hand, the monitoring of the symmetry of the melting pool utilizing thermography techniques.
Open Access
Validation of the use of concept maps as an evaluation tool for the teaching and learning of mechanical and industrial engineering
(Springer, 2024) Veiga Suárez, Fernando; Gil del Val, Alain; Iriondo, Edurne; Eslava Adot, Urko; Ingeniería; Ingeniaritza; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
This paper presents the experimental work developed to measure the learning process through concept map analysis. The development of a concept map is requested by the students for each chapter or theme of the subject. As a result, maps from engineering courses have been analyzed. The measurements carried out consider several parameters, such as individual and team map building, student progressive knowledge level, and map complexity. Concerning the complexity analysis, the focus is qualitative, and it is based on the data extracted from the concept maps elaborated by the students. The study, conducted during the 2018-2019 academic year, included students from various academic levels and institutions, such as the Public University of Navarra UPNA and the University of the Basque Country UPV-EHU, covering first-degree students of Bachelor's Degree in Mechanical Engineering and first-degree students of Master's Degree in Industrial Engineering at UPNA, third-degree students of Bachelor's Degree in Mechanical Engineering at UPV-EHU. The data collected from 37 individual maps in Industrial Drawing, 31 group maps in Industrial Drawing, 12 individual maps in Design of Machinery, and 12 group maps in Design of Machinery, along with a control group of 79 students who did not participate in any activity, provided valuable insights into the effectiveness of concept maps for evaluating understanding levels and learning outcomes across various engineering subjects and academic levels. The learning outcome of the students is treated to obtain the level of understanding of complex systems shown by the students through the concept maps previously drawn and the questionnaire answered by each student about the achievement of learning results through the use of concept maps. This work shows the research methodology established and the learning results achieved qualitatively: measuring the maps by means of a rubric, self-assessment based on a survey, and through the questionnaires. Also, the results obtained in the final exams have been compared. From the observed results, this methodology is presented as a suitable alternative for evaluating the correct acquisition of concepts in online teaching situations.
Open Access
The use of virtual sensors for bead size measurements in wire-arc directed energy deposition
(MDPI, 2024) Fernández Zabalza, Aitor; Veiga Suárez, Fernando; Suárez, Alfredo; Alfaro López, José Ramón; Ingeniería; Ingeniaritza
Having garnered significant attention in the scientific community over the past decade, wire-arc directed energy deposition (arc-DED) technology is at the heart of this investigation into additive manufacturing parameters. Singularly focused on Invar as the selected material, the primary objective revolves around devising a virtual sensor for the indirect size measurement of the bead. This innovative methodology involves the seamless integration of internal signals and sensors, enabling the derivation of crucial measurements sans the requirement for direct physical interaction or conventional measurement methodologies. The internal signals recorded, the comprising voltage, the current, the energy from the welding heat source generator, the wire feed speed from the feeding system, the traverse speed from the machine axes, and the temperature from a pyrometer located in the head were all captured through the control of the machine specially dedicated to the arc-DED process during a phase of optimizing and modeling the bead geometry. Finally, a feedforward neural network (FNN), also known as a multi-layer perceptron (MLP), is designed, with the internal signals serving as the input and the height and width of the bead constituting the output. Remarkably cost-effective, this solution circumvents the need for intricate measurements and significantly contributes to the proper layer-by-layer growth process. Furthermore, a neural network model is implemented with a test loss of 0.144 and a test accuracy of 1.0 in order to predict weld bead geometry based on process parameters, thus offering a promising approach for real-time monitoring and defect detection.