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• University of the Basque Country

Inconel® 718, known for its excellent mechanical properties in extreme conditions, presents machining challenges due to its low machinability. The chip formation process, influenced by its high ductility and low thermal conductivity, leads to material adhesion and high cutting forces. Ceramic tools have been proposed to mitigate these inconvenience...

In the present study, a comprehensive parametric analysis was carried out using the electrical discharge machining of Ti6Al4V, using pulse-on time, current, and pulse-off time as input factors with output measures of surface roughness and material removal rate. The present study also used two different nanopowders, namely alumina and nano-graphene,...

Two common types of internal defects of additively manufactured (AM) samples are lack-of-fusion and gas-entrapped porosities. These internal defects can have different physical origins and particular local characteristics (e.g., different shape, size). Thus, the use of reliable non-destructive inspection techniques is essential for the accurate ass...

This work aims to present a digital-twin for prediction of the mechanical behavior and failure of additive manufacturing components, considering the characteristics of heterogeneities, mainly porosities, which appear during the manufacturing process. Therefore, the proposed methodology is based on the development of a CT-based FEM model, as well as...

Nowadays, on-machine tool measurement (OMM) and coordinate measuring machine measurement (CMM) are the most common inspection methods. Although the ex-situ CMM measurements usually offers higher accuracy and reliability, OMM can inspect the workpiece without removing it from the machine tool. Therefore, it is possible to perform both in-process and...

One strategy that can allow an improvement in the quality of an industrial computed tomography (CT) image is finding an optimal specimen orientation for measurement. This implies to fix the specimen in an orientation that, for instance, minimizes the penetration lengths of the X-rays through the object material and avoid sharp thickness variations...

Multi-material structure fabrication has the potential to address some critical challenges in today’s industrial paradigm. While conventional manufacturing processes cannot deliver multi-material structures in a single operation, additive manufacturing (AM) has come up as an appealing alternative. In particular, laser-directed energy deposition (L-...

This work aims to present an XRCT-based FEM methodology to assess the influence of porosity defects on the mechanical behavior and failure of L-PBF AlSi10Mg components. Hence, the influence of defects on performance is estimated by means of XRCT scanning and analysis of porosity features, followed by mechanical FEM modelling of digitalized componen...

Internal thread profiles are used widely in manufacturing processes with the aim of assembling/disassembling different components during maintenance activities from the aeronautics sector until common industrial parts. The threading process is one of the last operations carried out to obtain those components, and consequently, it is an operation of...

Titanium represents a large part of critical structural and engine components on aircrafts. Surface residual stresses generated during machining are highly relevant regarding the fatigue behavior of these components. Nevertheless, the complex nature of the residual stress generation process prevents considering them during part and machining proces...

The scope of this work is to assess the influence of porosity on the mechanical behaviour of L-PBF Inconel 718. To this end, some test specimens were manufactured by L-PBF, according to ASTM E8/E8M. Afterwards, these specimens were scanned by means of XRCT in order to analyse the porosity of each one. The XRCT geometry generated by the previous ste...

The main objective of the proposed work was to analyse the influence of magnification and focal spot size scan settings on X-ray computed tomography (CT) measurements results under commercial threshold-based algorithms. The relationship between spatial resolution and contrast sensitivity in CT scans of different materials and the accuracy of the re...

There is undoubtedly an increasing trend towards the use of XRCT as a dimensional metrology tool, driven mainly by the proliferation of complex and hollow parts in the industry. While this technology is suitable for qualitative analysis, a consistent methodology is nevertheless needed, so that XRCT could be considered an accurate and reliable techn...

The scope of this work is to present a reverse engineering (RE) methodology to achieve accurate polygon models for 3D printing or additive manufacturing (AM) applications, as well as NURBS (Non-Uniform Rational B-Splines) surfaces for advanced machining processes. The accuracy of the 3D models generated by this RE process depends on the data acquis...

The aeronautical industry has begun to use advanced manufacturing and 3D printing for functional parts. The Product Design Laboratory (PDL) has studied the feasibility of manufacturing a part by Additive Manufacturing and has compared the geometric quality of the resulting part with those currently manufactured by plate assembly. Traditionally, we...

Harizko elektrohigadura bidezko ebaketa-prozesua (WEDM) ezinbestekoa da gaur egun, industriak gainazal-akaberen eta dimentsio-perdoien inguruan eskatzen dituen fabrikazio-betekizun zorrotzak betetzeko. Prozesuari buruzko ezagutzarekin batera softwarearen garapena integratzen duen ingurune batetik abiatuta, makina adimendunaren funtzionamenduaren he...

Theoretical models of manufacturing processes provide a valuable insight into physical phenomena but their application to practical industrial situations is sometimes difficult. In the context of Industry 4.0, artificial intelligence techniques can provide efficient solutions to actual manufacturing problems when big data are available. Within the...

For many industrial sectors, high-added value components are related to high accuracy manufacturing technologies. Wire Electrical Discharge Machining (WEDM) is an advanced non-conventional machining method commonly used in the production of precision components in extremely hard materials. The precision of the process depends largely on the deforma...

Wire deformation and vibration are classical topics of WEDM research. Many high-added value components (aerospace, medical, automotive…) benefit from the very tight tolerances that can be achieved by using wire EDM. However, there are some particular conditions in which the required accuracy is not fulfilled, as in the case of low-radius circles cu...

The present times are changing and need new formulas that satisfy the need for effective transfer between universities and companies. In the Basque Country, attending to this demand the Aeronautics Advanced Manufacturing Center (CFAA) has been founded. This center belongs to the University of the Basque Country (UPV/EHU) and has several companies r...

The wire electro-discharge machining (WEDM) is a widely-used machining process suitable to achieve the increasingly demanding precision requirements imposed by industry. Nevertheless, the use of conventional WEDM machines under some complex geometrical conditions makes sometimes difficult to fulfill these requirements, which is a topic of interest...

Manufacturing high aspect ratio slots in low machinability aeronautical materials using conventional machining methods is an arduous work. Electrical discharge machining has become an appropriate solution to carry out this task due to the independence of this process from material properties such as hardness or machinability. Former works show that...

The wire electrical-discharge machining process (WEDM) is a widely-used technology which can achieve the requirements needed by industry, such complex geometries and precision. Cutting process control in WEDM becomes essential in terms of surface finish and dimensional tolerances. When a cut is made in a variable workpiece thickness, the process be...

Grind-hardening is a manufacturing process that uses the heat generated within the grinding zone in order to produce surface hardening. After the process, workpieces present dimensional inaccuracies and a poor surface finish. Thus, a finishing grinding operation has to be carried out. For a successful implementation of the whole process, two proble...

There is a growing interest in the machining of micro-holes with high aspect-ratio in difficult-to-machine alloys for the aerospace industry. Processes based on Electro Discharge Machining (EDM) and developed for the manufacture of both micro-electrode and micro-hole are actually used, but most of them involve micro-EDM machines. In this work, the...

Electrical discharge milling-based processes are a good alternative for the manufacturing of micro-tools. However, some limitations must be considered both on the fields of process cost and control of surface characteristics. The inverse slab electrical discharge milling (ISEDM) process is an economic alternative to other high-precision high-cost m...

Grind-hardening is an innovative manufacturing process that takes advantage of the high amount of heat generated in the contact zone to produce a martensitic phase transformation in the subsurface layer of the workpiece. However, for a successful industrial implementation of the process, the closed loop control of the hardening depth is essential....

The grind-hardening process uses the heat generated within the grinding zone in order to produce surface hardening of the workpiece. However, after the process, workpieces present dimensional inaccuracies and poor surface roughness. Thus, a final grinding operation has to be performed. For an industrial implementation of the whole process, two prob...

Holes of 0.3-0.4 mm diameter and large depths are typical features in aerospace components of Ni-based and Ti-based alloys. The EDM process is a popular manufacturing method for this type of precision holes in difficult-to-machine materials. Optimization of this technology requires taking into account different aspects such as process parameters, e...

The EDM process is adequate for machining of narrow slots in low machinability materials, such as Ni based alloys used for aeronautical applications. This paper studies the influence of main process parameters involved in this process. The objective is to determine the effect of parameters related to the discharge process (current, pulse time and s...

Important research effort is currently being spent on reduction (if not complete removal) of lubricant consumption in machining operations. While scientific and industrial advances can be found in turning, milling and drilling technologies; advances in fluid reduction in grinding are still very limited. The main reason being abrasive processes gene...

Electrical discharge machining is a popular non-traditional machining process, optimum for accurate machining of complex geometries in hard materials. EDM has been used for decades for machining pieces for the aeronautical industry, but surface integrity, and consequently the reliability of the machined parts have been questioned for long time due...

The use of fluids in grinding is necessary to carry out an optimized process that avoids any kind of damage in the ground workpieces. However, the use of fluids in machining processes presents some problems as the economic one and the environmental one. The present work analyzes the industrial viability of a new solution to avoid the use of fluids...

Grinding is a stochastic process applied in the last stages of the manufacturing cycle. In last decades, grinding research has focused on prediction of thermal damage on ground workpiece since it is of considerable importance from both research and industrial perspectives. A number of numerical and analytical thermal models have been carried out so...

The process of Wire Electrical Discharge Machining (WEDM) has experienced a dramatic growth in the last years. Together with the new requirements imposed by customer needs, globalization of the markets has brought about a new scenario in which competitiveness is the keyword. In the case of WEDM, it is only possible from a perspective that integrate...

This paper analyses the technological capabilities of a novel rotary (EDM) electrical discharge machining process for the manufacturing of high aspect ratio cylindrical micro-components. The process is called Inverse Electrical Discharge Grinding (ISEDM). An experimental analysis has been carried out on high speed steel (tool steel Vanadis 23), usi...

Manufacturing of micro-pins with diameter less than 1 mm is a field of great interest both in research and in industrial application. There is a wide variety of components of low-diameter cylindrical geometry for various applications, including precision products such as gear shafts, valves, shafts, and channels of micro-fluidic systems, parts for...

Grinding process using superabrasive metal-bonded wheels is unavoidably linked to long and inefficient truing and dressing processes. This document presents the application of electro-discharge dressing process as an alternative to form wheels. The accuracy of the process and its efficiency has been analyzed on wheels of different grit size. To do...

Temperature measurement in grinding has been a widely analyzed field in the study of the process. Temperatures in grinding are too difficult to measure due to the high gradients in the ground workpiece. A lot of different methods have been employed by many researches in the last years. In this paper the use of thermocouples is analyzed attending to...

The European Higher Education Area has entailed some upheaval since it has involved deep changes in university education. Among the subjects taught in technical education such as Manufacturing Technologies, which involve strong experimental contents, the use of specific tools is helpful for better understanding of such subjects. This article highli...

The adaptation of universities to the European Higher Education Area (EHEA) plays an essential role in society, creating new knowledge, transferring it to students by means of new and more active methodologies aimed at learning that will enable students to put everything they learn into practice. However, such methodologies are not equally applicab...

The increased concern for environment and sustainability are pushing machining operations towards the reduction or even complete elimination of cutting fluids. Grinding is not excluded from this objective, but greater difficulties appear due to the nature of the material removal mechanisms. In this work, two approaches aiming at the optimization of...

The electrical discharge machining (EDM) process is a popular non-traditional machining process, but, although it is widely used in industry, there is still a lack of scientific knowledge about its fundamentals. This paper discusses some aspects of the discharge process at the sight of the results obtained with a previously developed thermal model,...

Important research efforts are being devoted to the analysis and optimization of grinding operations. Due to the large number of variables involved in the process, a deeper understanding of the nature of contact mechanics between wheel and workpiece is required. The possibility of a sound estimation of the actual contact length is a critical issue,...

Although there are already successful industrial experiences in other machining industries with the elimination of coolants, this is not so in the grinding industry due to the large amounts of generated heat that must be evacuated from the contact zone. In this work, a new approach to the elimination of fluids in grinding is presented. The technolo...

Superabrasive grinding is a high efficiency process used in special applications such as high speed grinding, creep feed grinding, and Quick-Point. Although the maximum efficiency is obtained by metallic bonded wheels due to their wear resistance, their hardness makes almost impossible to dress them properly. Vitrified bonded wheels are now being u...

In recent years, efforts have been put on modelling of the EDM process, being thermal modelling of the process one promising alternative. In a previous publication an original model of the EDM process was presented; even though predictions made by the proposed model show very high accuracy, there are still some aspects regarding the modelling of th...

Hard metal is characterised by having a extremely high hardness and high wear resistance, and those characteristics make difficult conventional machining. Electrical Discharge Machining (EDM) has become an attractive and feasible method for the manufacturing of precision hard metal tooling, and it is now an alternative to classical diamond grinding...

Electrical Discharge Machining (EDM) is a non‐conventional machining process whose thermoelectric nature makes it suitable for the machining of any material, regardless of its hardness and of its brittleness, as long as it conducts electricity. Despite EDM is a popular process in industry, the fact that it involves phenomena of very distinct nature...

Taper-cutting is a common application of the wire electrical discharge machining (WEDM) process used for the production of parts with complex geometry such as extrusion dies in wear-resistant materials, cutting dies, etc. During cutting, the wire is subject to deformation, resulting in deviations in the inclination angle of machined parts. This fac...

The paradigm the new European Higher Education Area places us in together with the teaching/learning guidelines and models demands the teacher adapt his/her function considering new methods which locate the students in the centre of this process. In this context the experience of the subject 'Advanced forming and moulding techniques' taught in 5(th...

The electrical discharge machining (EDM) process is optimum for accurate machining of complex geometries in hard materials, as those required in the tooling industry. It has become by far the most popular among the non-conventional machining processes. However, although a large number of EDM machines are sold every year, available knowledge of the...

The electrical discharge machining (EDM) process is, by far, the most popular amongst the non-conventional machining processes. The technology is optimum for accurate machining of complex geometries in hard materials, as those required in the tooling industry. However, although a large number of EDM machines are sold every year, scientific knowledg...

Wire electro discharge machining (WEDM) has become one of the most popular processes for producing precise geometries in hard materials, such as those used in the tooling industry. The so-called taper-cutting involves the generation of inclined ruled surfaces, and it is especially important in the manufacturing of tooling requiring draft angles. In...

Wire electro discharge machining (WEDM) has become one of the most popular processes for producing precise geometries in hard materials, such as those used in the tooling industry. Since it is recognized as a precision process, optimization of different aspects related to dimensional accuracy is a classic research topic. The so-called taper-cutting...

The integration of Simulation and Off-line Programming techniques in highly automated manufacturing systems, like in the Automobile industry, is justified for the multiple benefits that it reports. The Simulation improves the design of the manufacturing system, facilitates the study of design modifications and guarantees realibility and flexibility...