Browsing by Author "Veiga, Fernando"
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Item Analysis of the Machining Process of Inconel 718 Parts Manufactured by Laser Metal Deposition(2019-07-01) Ostra, Txomin; Alonso, Unai; Veiga, Fernando; Ortiz, Mikel; Ramiro, Pedro; Alberdi, Amaia; FABRIC_INTEL; Tecnalia Research & InnovationLaser metal deposition (LMD) is an additive manufacturing process that allows the manufacturing of near-net-shape products. This could mean significant savings in terms of materials and costs in the manufacturing of high-performance components for the aeronautical industry. In this work, an analysis of how the LMD processing of alloy 718 affects the final machining has been carried out. For this purpose, a comparative study has been done by means of the monitoring of the end milling process of a part manufactured by LMD and a rough-milled part from forged material. Differences between process outputs such as chip morphology and cutting forces were studied. Material characteristics such as microstructure, hardness and mechanical properties were also analyzed.Item Analysis of the Machining Process of Titanium Ti6Al-4V Parts Manufactured by Wire Arc Additive Manufacturing (WAAM)(2020-02-01) Veiga, Fernando; Gil Del Val, Alain; Suárez, Alfredo; Alonso, Unai; Tecnalia Research & Innovation; FABRIC_INTELIn the current days, the new range of machine tools allows the production of titanium alloy parts for the aeronautical sector through additive technologies. The quality of the materials produced is being studied extensively by the research community. This new manufacturing paradigm also opens important challenges such as the definition and analysis of the optimal strategies for finishing-oriented machining in this type of part. Researchers in both materials and manufacturing processes are making numerous advances in this field. This article discusses the analysis of the production and subsequent machining in the quality of TI6Al4V produced by Wire Arc Additive Manufacturing (WAAM), more specifically Plasma Arc Welding (PAW). The promising results observed make it a viable alternative to traditional manufacturing methods.Item Analysis of the Wall Geometry with Different Strategies for High Deposition Wire Arc Additive Manufacturing of Mild Steel(Multidisciplinary Digital Publishing Institute (MDPI), 2020-07) Aldalur, Eider; Veiga, Fernando; Suárez, Alfredo; Bilbao, Jon; Lamikiz, AitzolAdditive manufacturing has gained relevance in recent decades as an alternative to the manufacture of metal parts. Among the additive technologies, those that are classified as Directed Energy Deposition (DED) are characterized by their high deposition rate, noticeably, Wire Arc Additive Manufacturing (WAAM). However, having the inability to produce parts with acceptable final surface quality and high geometric precision is to be considered an important disadvantage in this process. In this paper, different torch trajectory strategies (oscillatory motion and overlap) in the fabrication of low carbon steel walls will be compared using Gas Metal Arc Welding (GMAW)-based WAAM technology. The comparison is done with a study of the mechanical and microstructural characteristics of the produced walls and finally, addressing the productivity obtained utilizing each strategy. The oscillation strategy shows better results, regarding the utilization rate of deposited material and the flatness of the upper surface, this being advantageous for subsequent machining steps.Item Characterization of Inconel 718® superalloy fabricated by wire Arc Additive Manufacturing: effect on mechanical properties and machinability: effect on mechanical properties and machinability(2021-09) Alonso, Unai; Veiga, Fernando; Suárez, Alfredo; Gil Del Val, Alain; Tecnalia Research & Innovation; FABRIC_INTELWire and Arc Additive Manufacturing has the potential to become an appropriate technique to produce large complex-shaped metallic parts. However, a post-processing machining operation is necessary to reach the final geometry. In this work, Inconel 718 walls were manufactured in a monitored environment and their microstructure and mechanical properties were characterised. Then, slot milling operations were performed to investigate the influence of cutting speed and machining direction. The conclusions drawn from this article can be used as a guide for a correct definition of strategies and milling parameters. It was observed that at higher cutting speeds a better surface quality and lower torques are obtained. Moreover, the main novelty of this work is that is shows the influence of the anisotropy of WAAM-Inconel 718 on its machinability. Milling along the torch's travel direction offers better dimensional tolerance values with lower cutting torques, being more favourable than machining in the building direction.Item Effect of the Heat Input on Wire-Arc Additive Manufacturing of Invar 36 Alloy: Microstructure and Mechanical Properties: Microstructure and Mechanical Properties(2022-04-07) Veiga, Fernando; Suárez, Alfredo; Artaza, Teresa; Aldalur, Eider; Tecnalia Research & Innovation; FABRIC_INTELInvar, also known as FeNi36, is a material of great interest due to its unique properties, which makes it an excellent alterna tive for sectors such as tooling in aeronautics and aerospace. Its manufacture by means of wire arc additive manufacturing (WAAM) technology could extend its use. This paper aims to evaluate the comparison of two of the most widespread WAAM technologies: plasma arc welding (PAW) and gas metal arc welding (GMAW). This comparison is based on the analysis of wall geometry, metallography, and mechanical properties of the material produced by both technologies. The results show a slight increase in toughness and elongation before fracture and worse tensile strength data in the case of PAW, with aver age values of 485 MPa for ultimate tensile strength (UTS), 31% for elongation and 475 MPa, 40% in GMAW and PAW, respectively. All results gathered from the analysis show the possibility of successful manufacturing of Invar by means of WAAM technologies. The novelties presented in this paper allow us to establish relationships between the thermal input of the process itself and the mechanical and metallographic properties of the material produced.Item Effect of the Metal Transfer Mode on the Symmetry of Bead Geometry in WAAM Aluminum(2021-07-10) Veiga, Fernando; Suárez, Alfredo; Aldalur, Eider; Bhujangrao, Trunal; Tecnalia Research & Innovation; FABRIC_INTELThe symmetrical nature in the case of wall fabrication by wire arc additive manufacturing (WAAM) has been observed in the literature, but it has not been studied as a source of knowledge. This paper focuses on the comparative study of three drop transfer methods employing Gas Metal Arc Welding (GMAW) technology, one of the most reported for the manufacture of aluminum alloys. The transfer modes studied are the well-known pulsed GMAW, cold arc, and the newer pulsed AC. The novelty of the last transfer mode is the reversal of the polarity during the preparation phase of the substance for droplet deposition. This study compares the symmetry of zero beads to determine the best parameters and transfer modes for wire arc additive manufacturing of 5 series aluminum. The pulsed transfer modes show values of 0.6 for symmetry ratio, which makes them more interesting strategies than cold arc with a symmetry ratio of 0.5. Furthermore, the methodology proposed in this study can be extrapolated to other materials manufactured with this technology.Item Experimental Investigation of the Influence of Wire Arc Additive Manufacturing on the Machinability of Titanium Parts(2020-01) Alonso, Unai; Veiga, Fernando; Suárez, Alfredo; Artaza, Teresa; Tecnalia Research & Innovation; FABRIC_INTELThe manufacturing of titanium airframe parts involves significant machining and low buy-to-fly ratios. Production costs could be greatly reduced by the combination of an additive manufacturing (AM) process followed by a finishing machining operation. Among the different AM alternatives, wire arc additive manufacturing (WAAM) offers deposition rates of kg/h and could be the key for the production of parts of several meters economically. In this study, the influence of the manufacturing process of Ti6Al4V alloy on both its material properties and machinability is investigated. First, the mechanical properties of a workpiece obtained by WAAM were compared to those in a conventional laminated plate. Then, drilling tests were carried out in both materials. The results showed that WAAM leads to a higher hardness than laminated Ti6Al4V and satisfies the requirements of the standard in terms of mechanical properties. As a consequence, higher cutting forces, shorter chips, and lower burr height were observed for the workpieces produced by AM. Furthermore, a metallographic analysis of the chip cross-sectional area also showed that a serrated chip formation is also present during drilling of Ti6Al4V produced by WAAM. The gathered information can be used to improve the competitiveness of the manufacturing of aircraft structures in terms of production time and cost.Item High-Temperature Mechanical Properties of IN718 Alloy: Comparison of Additive Manufactured and Wrought Samples(Multidisciplinary Digital Publishing Institute (MDPI), 2020-08-09) Bhujangrao, Trunal; Veiga, Fernando; Suárez, Alfredo; Iriondo, Edurne; Mata, Franck GirotWire Arc Additive Manufacturing (WAAM) is one of the most appropriate additive manufacturing techniques for producing large-scale metal components with a high deposition rate and low cost. Recently, the manufacture of nickel-based alloy (IN718) using WAAM technology has received increased attention due to its wide application in industry. However, insufficient information is available on the mechanical properties of WAAM IN718 alloy, for example in high-temperature testing. In this paper, the mechanical properties of IN718 specimens manufactured by the WAAM technique have been investigated by tensile tests and hardness measurements. The specific comparison is also made with the wrought IN718 alloy, while the microstructure was assessed by scanning electron microscopy and X-ray diffraction analysis. Fractographic studies were carried out on the specimens to understand the fracture behaviour. It was shown that the yield strength and hardness of WAAM IN718 alloy is higher than that of the wrought alloy IN718, while the ultimate tensile strength of the WAAM alloys is difficult to assess at lower temperatures. The microstructure analysis shows the presence of precipitates (laves phase) in WAAM IN718 alloy. Finally, the effect of precipitation on the mechanical properties of the WAAM IN718 alloy was discussed in detail.Item Influence of Axial Depth of Cut and Tool Position on Surface Quality and Chatter Appearance in Locally Supported Thin Floor Milling(2022-01-19) Casuso, Mikel; Rubio-Mateos, Antonio; Veiga, Fernando; Lamikiz, Aitzol; Tecnalia Research & Innovation; FABRIC_INTELThin floor machining is a challenging and demanding issue, due to vibrations that create poor surface quality. Several technologies have been developed to overcome this problem. Ad hoc fixtures for a given part geometry lead to meeting quality tolerances, but since they lack flexibility, they are expensive and not suitable for low manufacturing batches. On the contrary, flexible fixtures consisting of vacuum cups adaptable to a diversity of part geometries may not totally avoid vibrations, which greatly limits its use. The present study analyses the feasibility of thin floor milling in terms of vibration and roughness, in the cases where milling is conducted without back support, a usual situation when flexible fixtures are employed, so as to define the conditions for a stable milling in them and thus avoid the use of ad hoc fixtures. For that purpose, the change of modal parameters due to material removal and its influence on chatter appearance have been studied, by means of stability lobe diagrams and Fourier Transform analysis. Additionally, the relationship between surface roughness and chatter frequency, tooth passing frequency, and spindle frequency have been studied. Ploughing effect has also been observed during milling, and the factors that lead to the appearance of this undesirable effect have been analyzed, in order to avoid it. It has been proven that finish milling of thin floors without support in the axial direction of the mill can meet aeronautic tolerances and requirements, providing that proper cutting conditions and machining zones are selected.Item Influence of Heat Input on the Formation of Laves Phases and Hot Cracking in Plasma Arc Welding (PAW) Additive Manufacturing of Inconel 718(2020-06) Artaza, Teresa; Bhujangrao, Trunal; Suárez, Alfredo; Veiga, Fernando; Lamikiz, Aitzol; FABRIC_INTEL; Tecnalia Research & InnovationNickel-based alloys have had extensive immersion in the manufacturing world in recent decades, especially in high added value sectors such as the aeronautical sector. Inconel 718 is the most widespread in terms of implantation. Therefore, the interest in adapting the manufacture of this material to additive manufacturing technologies is a significant objective within the scientific community. Among these technologies for the manufacture of parts by material deposition, plasma arc welding (PAW) has advantages derived from its simplicity for automation and integration on the work floor with high deposition ratios. These characteristics make it very economically appetizing. However, given the tendency of this material to form precipitates in its microstructure, its manufacturing by additive methods is very challenging. In this article, three deposition conditions are analyzed in which the energy and deposition ratio used are varied, and two cooling strategies are studied. The interpass cooling strategy (ICS) in which a fixed time is expected between passes and controlled overlay strategy (COS) in which the temperature at which the next welding pass starts is controlled. This COS strategy turns out to be advantageous from the point of view of the manufacturing time, but the deposition conditions must be correctly defined to avoid the formation of Laves phases and hot cracking in the final workpiece.Item Model for the Prediction of Deformations in the Manufacture of Thin-Walled Parts by Wire Arc Additive Manufacturing Technology(2021-04-21) Casuso, Mikel; Veiga, Fernando; Suárez, Alfredo; Bhujangrao, Trunal; Aldalur, Eider; Artaza, Teresa; Amondarain, Jaime; Lamikiz, Aitzol; FABRIC_INTEL; Tecnalia Research & InnovationGas Metal Arc Welding (GMAW) is a manufacturing technology included within the differentWire Arc Additive Manufacturing alternatives. These technologies have been generating great attention among scientists in recent decades. Its main qualities that make it highly productive with a large use of material with relatively inexpensive machine solutions make it a very advantageous technology. This paper covers the application of this technology for the manufacture of thin-walled parts. A finite element model is presented for estimating the deformations in this type of parts. This paper presents a simulation model that predicts temperatures with less than 5% error and deformations of the final part that, although quantitatively has errors of 20%, qualitatively allows to know the deformation modes of the part. Knowing the part areas subject to greater deformation may allow the future adaptation of deposition strategies or redesigns for their adaptation. These models are very useful both at a scientific and industrial level since when we find ourselves with a technology oriented to Near Net Shape (NNS) manufacturing where deformations are critical for obtaining the final part in a quality regime.Item A non-destructive quality assessment for blind-fastener installations based on the combination of ultrasound techniques and real-time monitoring of the fastening process(2016-05-01) Camacho, Javier; Rivero, Asun; Veiga, Fernando; Guzman, Desiree; SG; Tecnalia Research & InnovationThis paper proposes and evaluates a non-destructive method in assessing the quality of blind-fastener installations. The method is based on combining the time of flight of an ultrasonic pulse along the pin of the fastener and the fastener installation time. The former has to be measured after the fastening process; the latter has to be acquired at the machine during the fastening. The tests performed on carbon fibre reinforced plastic laminates joined by means of ABS0257 blind fasteners have proved that the method can distinguish incorrectly installed fasteners due to improper grip selection. The hit rate of the developed non-destructive method is above 95 % for the tested range of fastener sizes. The implementation of this method might prevent the use of extra fasteners, currently required, in order to compensate for the uncertainty of blind-fastener installationsItem On-Line Monitoring of Blind Fastener Installation Process(2019) Camacho, Javier; Veiga, Fernando; Penalva, Mari Luz; Diez-Olivan, Alberto; Deitert, Lutz; López de Lacalle, Norberto; Tecnalia Research & Innovation; FABRIC_INTELBlind fasteners are of special interest for aircraft construction since they allow working on joints where only one side is accessible, as is the case in many common aerospace box-type structures, such as stabilizers and flaps. This paper aims to deliver an online monitoring method for the detection of incorrect installed blind fasteners. In this type of fastener, the back side of the assembly is not accessible, so monitoring the process installation is suitable as a system to assess the formed head at the back side with no access. The solution proposed consists of an on-line monitoring system that is based on sensor signals acquired during the installation. The signals are conveniently analyzed in order to provide an evaluation outcome on how the fastener was installed. This new method will help production to decrease/eliminate time and cost-intensive inspections and fasteners over installation in structures. The decrease of the number of installed fasteners will also contribute to weight savings and will reduce the use of resources.Item Oversizing Thread Diagnosis in Tapping Operation(2021-03-25) Gil Del Val, Alain; Veiga, Fernando; Penalva, Mariluz; Arizmendi, Miguel; Tecnalia Research & Innovation; FABRIC_INTELAutomotive, railway and aerospace sectors require a high level of quality on the thread profiles in their manufacturing systems knowing that the tapping process is a complex manufacturing process and the last operation in a manufacturing cell. Therefore, a multivariate statistical process control chart, for each tap, is presented based on the principal components of the torque signal directly measured from spindle motor drive to diagnosis the thread profile quality. This on-line multivariate control chart has implemented an alarm to avoid defected screw threads (oversized). Therefore, it could work automatically without any operator intervention assessing the thread quality and the safety is guaranteed during the tapping process.Item Predicted Torque Model in Low-Frequency-Assisted Boring (LFAB) Operations(2021-06-24) Veiga, Fernando; Gil Del Val, Alain; Penalva, Mari Luz; Pereira, Octavio; Suárez, Alfredo; López de Lacalle Marcaide, Luis Norberto; Tecnalia Research & Innovation; FABRIC_INTELA low-frequency-assisted boring operation is a key cutting process in the aircraft manufacturing sector when drilling deep holes to avoid chip clogging based on chip breakage and, consequently, to reduce the temperature level in the cutting process. This paper proposes a predicted force model based on a commercial control-supported chip breaking function without external vibration devices in the boring operations. The model was fitted by conventional boring measurements and was validated by vibration boring experiments with different ranges of amplitude and frequency. The average prediction error is around 10%. The use of a commercial function makes the model more attractive for the industry because there is no need for intrusive vibration sensors. The low-frequency assisted boring (LFAB) operations foster the chip breakage. Finally, the model is generic and can be used for different cutting materials and conditions. Roughness is improved by 33% when vibration conditions are optimal, considered as a vibration amplitude of half the feed per tooth. This paper presents, as a novelty, the analysis of low-frequency vibration parameters in boring processes and their effect on chip formation and internal hole roughness. This has a practical significance for the definition of a methodology based on the torque model for the selection of conditions on other hole-making processes, cutting parameters and/or materials.Item Study of the Mechanical Behavior of Topologically Optimized Arc Wire Direct Energy Deposition Aerospace Fixtures(2022-02-24) Suárez, Alfredo; Veiga, Fernando; Bhujangrao, Trunal; Aldalur, Eider; FABRIC_INTEL; Tecnalia Research & InnovationThe reliability and performance qualification of additively manufactured metal parts is essential for their successful and safe use in engineering applications. Additive Manufacturing (AM) allows parts to be produced more easily than traditional manufacturing. Arc Wire Direct Energy Deposition (AW-DED) is one of the lesser-known metal additive manufacturing technologies. It has enormous potential for large-scale 3D printing applications in the aerospace industry. However, in the aerospace industry, one of the main challenges today is to reduce the weight of components without compromising their structural functionality. Topology optimization offers design engineers the opportunity to create lightweight and complex structural parts. In arc wire direct energy deposition (AW-DED) processes, processing parameters affect material microstructure features, overall part quality, and integrity, as well as bulk mechanical behavior. To address such challenges, the investigation presented in this paper describes a novel digital design approach combining topology optimization, process simulations, and size optimization of the tool components used in the aerospace industry to address effects caused during manufacturing by using Finite Element Modeling (FEM) simulations. This can lead to reduced costs, development time, material consumption, and product weight. Due to the flexibility mentioned above, parts designed for AM have the same structural load as conventional parts but with reduced mass and better part design. The results of this application are discussed in depth in this paper. This is a new research work with useful results and conclusions in the methodology for the evaluation of mechanical behavior of topologically optimized metal additive manufactured components. For this purpose, aerospace fixtures have been topologically designed by means of AW-DED-process-oriented techniques. Aerospace fixtures are normally used in the aerospace industry to support and hold various components. These new design paradigms make it possible to save on material costs oriented toward more sustainable and flexible manufacturing.Item Thread Quality Control in High-Speed Tapping Cycles(2020-02) Gil Del Val, Alain; Veiga, Fernando; Suárez, Alfredo; Arizmendi, Mikel; Tecnalia Research & Innovation; FABRIC_INTELThread quality control is becoming a widespread necessity in manufacturing to guarantee the geometry of the resulting screws on the workpiece due to the high industrial costs. Besides, the industrial inspection is manual provoking high rates of manufacturing delays. Therefore, the aim of this paper consists of developing a statistical quality control approach acquiring the data (torque signal) coming from the spindle drive for assessing thread quality using different coatings. The system shows a red light when the tap wear is critical before machining in unacceptable screw threads. Therefore, the application could reduce these high industrial costs because it can work self-governance.Item Threading Performance of Different Coatings for High Speed Steel Tapping(2020-05-01) Gil Del Val, Alain; Veiga, Fernando; Pereira, Octavio; Lopez De Lacalle, Luis Norberto; Tecnalia Research & Innovation; FABRIC_INTELThreading holes using tapping tools is a widely used machining operation in the industry. This manufacturing process involves a great tool immersion in the part, which involves both friction and cutting. This makes the use of coatings critical to improving tool life. Four coatings are used based on Physical vapor deposition (PVD) technology—TiN, TiCN, TiAlN and TiAlN+WC/C are compared to uncoated tool performance. The effect of various coatings on the life ofM12 _ 1.5 tapping tools during threading of through holes 20 mm deep, in GG25 casting plates, dry and applying cutting speed of 50 m/min. The end-of-life criterion has been established based on a cutting torque of 16 N-m. Taking the uncoated tap as a basis for comparison, it is observed that coatings based on PVD technologies increase tool life doubling in the most advantageous case with the TiAlN coating. PVD type coatings provide better protection towear at cylindrical area of the tool, where the thread profile is finished, than uncoated taps. The teeth located in the cone-cylinder transition zone of the taps suffer the most wear regardless of the coating. However, taps coated with TiAlN+WC/C wear level values is lowest of all the coatings tested, which indicates a strong reinforcement in these teeth.Item Three-Dimensional Finite Element Modelling of Sheet Metal Forming for the Manufacture of Pipe Components: Symmetry Considerations: Symmetry Considerations(2022-01-25) Bhujangrao, Trunal; Veiga, Fernando; Penalva, Mariluz; Costas, Adriana; Ruiz, Cristina; Tecnalia Research & Innovation; FABRIC_INTELThe 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.Item Validation of the Mechanical Behavior of an Aeronautical Fixing Turret Produced by a Design for Additive Manufacturing (DfAM)(2022-05-27) Veiga, Fernando; Bhujangrao, Trunal; Suárez, Alfredo; Aldalur, Eider; Goenaga, Igor; Gil-Hernandez, Daniel; Tecnalia Research & Innovation; FABRIC_INTEL; MAQUINAS; SMART_MONThe design of parts in such critical sectors as the manufacturing of aeronautical parts is awaiting a paradigm shift due to the introduction of additive manufacturing technologies. The manufacture of parts designed by means of the design-oriented additive manufacturing methodology (DfAM) has acquired great relevance in recent years. One of the major gaps in the application of these technologies is the lack of studies on the mechanical behavior of parts manufactured using this methodology. This paper focuses on the manufacture of a turret for the clamping of parts for the aeronautical industry. The design of the lightened turret by means of geometry optimization, the manufacture of the turret in polylactic acid (PLA) and 5XXX series aluminum alloy by means of Wire Arc Additive Manufacturing (WAAM) technology and the analysis by means of finite element analysis (FEA) with its validation by means of a tensile test are presented. The behavior of the part manufactured with both materials is compared. The conclusion allows to establish which are the limitations of the part manufactured in PLA for its orientation to the final application, whose advantages are its lower weight and cost. This paper is novel as it presents a holistic view that covers the process in an integrated way from the design and manufacture to the behaviour of the component in use