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With the advent of disruptive additive manufacturing (AM), there is an increasing interest and demand of high mechanical property aluminium parts built directly by these technologies. This has led to the need for continuous improvement of AM technologies and processes to obtain the best properties in aluminium samples and develop new alloys. This study has demonstrated that porosity can be reduced below 0.035% in area in Al-Mg samples manufactured by CMT-based WAAM with commercial filler metal wires by selecting the correct shielding gas, gas flow rate, and deposition strategy (hatching or circling). Three phase Ar+O2+N2O mixtures (Stargold®) are favourable when the hatching deposition strategy is applied leading to wall thickness around 6 mm. The application of circling strategy (torch movement with overlapped circles along the welding direction) enables the even build-up of layers with slightly thicker thickness (8 mm). In this case, Ar shielding gas can effectively reduce porosity if proper flow is provided through the torch. Reduced gas flows (lower than 30 Lmin) enhance porosity, especially in long tracks (longer than 90 mm) due to local heat accumulation. Surprisingly, rather high porosity levels (up to 2.86 area %) obtained in the worst conditions, had a reduced impact on the static tensile test mechanical properties, and yield stress over 110 MPa, tensile strength over 270 MPa, and elongation larger than 27% were achieved either for Ar circling, Ar hatching, or Stargold® hatching building conditions. In all cases anisotropy was lower than 11%, and this was reduced to 9% for the most appropriate shielding conditions. Current results show that due to the selected layer height and deposition parameters there was a complete re-melting of the previous layer and a thermal treatment on the prior bottom layer that refined the grain size removing the original dendritic and elongated structure. Under these conditions, the minimum reported anisotropy levels can be achieved.
Maider Arana; Eneko Ukar; Iker Rodriguez; Amaia Iturrioz; Pedro Alvarez. Strategies to Reduce Porosity in Al-Mg WAAM Parts and Their Impact on Mechanical Properties. Metals 2021, 11, 524 .
AMA StyleMaider Arana, Eneko Ukar, Iker Rodriguez, Amaia Iturrioz, Pedro Alvarez. Strategies to Reduce Porosity in Al-Mg WAAM Parts and Their Impact on Mechanical Properties. Metals. 2021; 11 (3):524.
Chicago/Turabian StyleMaider Arana; Eneko Ukar; Iker Rodriguez; Amaia Iturrioz; Pedro Alvarez. 2021. "Strategies to Reduce Porosity in Al-Mg WAAM Parts and Their Impact on Mechanical Properties." Metals 11, no. 3: 524.
The present paper evaluates the misalignment and geometry distortion of the standard National Institute of Standards and Technology (NIST) test artifact in Inconel 718 alloy, when several layers with and without supports are employed to manufacture it by the Selective Laser Melting (SLM) process. To this end, a coordinate-measuring machine (CMM) is used to measure the geometrical distortion in each manufacturing configuration, following the same measurement protocol. The results show that the laser path strategy favors a thermal gradient which, consequently, induces geometrical distortions in the part. To prove this hypothesis, a numerical simulation is performed to determine the thermal gradient and the pattern of the residual stresses. It was found that the geometrical distortion certainly depends on the position of the feature position and laser strategy, where thermal cycles and residual thermal stresses had an impact in the end-part geometry, especially if a high strength-to-weight ratio commonly used in aeronautics is present.
Silvia Martínez; Naiara Ortega; Diego Celentano; Antonio J. Sánchez Egea; Eneko Ukar; A. Lamikiz. Analysis of the Part Distortions for Inconel 718 SLM: A Case Study on the NIST Test Artifact. Materials 2020, 13, 5087 .
AMA StyleSilvia Martínez, Naiara Ortega, Diego Celentano, Antonio J. Sánchez Egea, Eneko Ukar, A. Lamikiz. Analysis of the Part Distortions for Inconel 718 SLM: A Case Study on the NIST Test Artifact. Materials. 2020; 13 (22):5087.
Chicago/Turabian StyleSilvia Martínez; Naiara Ortega; Diego Celentano; Antonio J. Sánchez Egea; Eneko Ukar; A. Lamikiz. 2020. "Analysis of the Part Distortions for Inconel 718 SLM: A Case Study on the NIST Test Artifact." Materials 13, no. 22: 5087.
Fabrikazio-prozesu gehigarri eta kengarrien arteko konbinaketa oso erabilgarria da geometria konplexuko eta balio-erantsi altuko piezen konponketarako. Prozesuak bateratzeko aukera hoberena, beraiek makinabakarrean barneratzea da. Alabaina, bateratze honetan erronka anitzak agertzen dira, besteak beste, mekanizazioprozesuan erabiltzen diren ebaketa-jariakinek jarraiko gehitze-prozesuan izan dezaketen eraginaren ezjakintasunaren ondorioz. Egoera honen aurrean, berotako trokelgintzan ohikoa den AISI H13aren kasurako ebaketa-jariakinarekin kutsaturiko gainazalean laser bidez materiala eranstean ager daitezkeen akatsen azterketa gauzatu da. Olio-maila anitzekin egin dira saiakuntzak eta gainazal garbian egindako erreferentziazko saiakuntzarekin alderatu dira lorturiko emaitzak. Aldaera morfologikoak nabaritzeaz gain, %100 olio-kontzentrazioko ebaketa-jariakina erabiltzen deneko kasuan erantsitako materiala arrakalatu egiten dela ikusi da, egoera honetan fabrikaturiko piezak baliogabetuz. Hortaz, AISI H13aren kasuan gehitze-prozesuaren aurretik gainazalean egon daitezkeen ebaketa-jariakinen garbiketa beharrezkoa dela ikusi da.
Jon Iñaki Arrizubieta; Magdalena Cortina; Marta Ostolaza; Aitzol Lamikiz; Eneko Ukar. Txirbil-harroketan erabilitako ebaketa-jariakinaren eragina laser bidezko prozesu gehigarrian konformaziorako trokelen konponketaren kasuan. EKAIA Euskal Herriko Unibertsitateko Zientzia eta Teknologia Aldizkaria 2020, 1 .
AMA StyleJon Iñaki Arrizubieta, Magdalena Cortina, Marta Ostolaza, Aitzol Lamikiz, Eneko Ukar. Txirbil-harroketan erabilitako ebaketa-jariakinaren eragina laser bidezko prozesu gehigarrian konformaziorako trokelen konponketaren kasuan. EKAIA Euskal Herriko Unibertsitateko Zientzia eta Teknologia Aldizkaria. 2020; ():1.
Chicago/Turabian StyleJon Iñaki Arrizubieta; Magdalena Cortina; Marta Ostolaza; Aitzol Lamikiz; Eneko Ukar. 2020. "Txirbil-harroketan erabilitako ebaketa-jariakinaren eragina laser bidezko prozesu gehigarrian konformaziorako trokelen konponketaren kasuan." EKAIA Euskal Herriko Unibertsitateko Zientzia eta Teknologia Aldizkaria , no. : 1.
Abrasive-cutting processes are widely used to obtain semi-finished products from metal bars, slabs, or tubes. Thus, the abrasive cutting-off process is applied when requiring precision cutting and productivity at a moderate price. Cut-off tools are discs composed of small abrasive particles embedded in a bonding material, called the binder. This work aims to compare the cutting performance of discs with different composition, in dry cutting of steel bars. To do that, disc wear was measured and disc final topography was digitalized in order to determine both disc surface wear patterns and if the abrasive particles bonding into the binder matrix was affected. In addition, X-Ray inspection gave information about the abrasive grit-binder bonding. Therefore, the method here presented allows identifying discs with a superior abrasive-cutting capability, by combining profilometry and tomography to define micrometrical aspects, grit size, and binder matrix structure. Results led to the conclusion that discs with high grit size and protrusion, high grit retention by bond material, and closer mesh of fiberglass matrix binder were the optimal solution.
Naiara Ortega; Vitaliy Martynenko; Daniela Perez; Daniel Martinez Krahmer; Luis Norberto López De Lacalle; Eneko Ukar. Abrasive Disc Performance in Dry-Cutting of Medium-Carbon Steel. Metals 2020, 10, 538 .
AMA StyleNaiara Ortega, Vitaliy Martynenko, Daniela Perez, Daniel Martinez Krahmer, Luis Norberto López De Lacalle, Eneko Ukar. Abrasive Disc Performance in Dry-Cutting of Medium-Carbon Steel. Metals. 2020; 10 (4):538.
Chicago/Turabian StyleNaiara Ortega; Vitaliy Martynenko; Daniela Perez; Daniel Martinez Krahmer; Luis Norberto López De Lacalle; Eneko Ukar. 2020. "Abrasive Disc Performance in Dry-Cutting of Medium-Carbon Steel." Metals 10, no. 4: 538.
In finishing processes, the quality of aluminum parts is mostly influenced by static and dynamic phenomena. Different solutions have been studied toward a stable milling process attainment. However, the improvements obtained with the tuning of process parameters are limited by the system stiffness and external dampers devices interfere with the machining process. To deal with this challenge, this work analyzes the suitability of elastomer layers as passive damping elements directly located under the part to be machined. Thus, exploiting the sealing properties of nitrile butadiene rubber (NBR), a suitable flexible vacuum fixture is developed, enabling a proper implementation in the manufacturing process. Two different compounds are characterized under axial compression and under finishing operations. The compression tests present the effect of the feed rate and the strain accumulative effect in the fixture compressive behavior. Despite the higher strain variability of the softer rubber, different milling process parameters, such as the tool feed rate, can lead to a similar compressive behavior of the fixture regardless the elastomer hardness. On the other hand, the characterization of these flexible fixtures is completed over AA2024 floor milling of rigid parts and compared with the use of a rigid part clamping. These results show that, as the cutting speed and the feed rate increases, due to the strain evolution of the rubber, the part quality obtained tend to equalize between the flexible and the rigid clamping of the workpiece. Due to the versatility of the NBR for clamping different part geometries without new fixture redesigns, this leads to a competitive advantage of these flexible solutions against the classic rigid vacuum fixtures. Finally, a model to predict the grooving forces with a bull-nose end mill regardless of the stiffness of the part support is proposed and validated for the working range.
Antonio Rubio-Mateos; Asuncion Rivero; Eneko Ukar; Aitzol Lamikiz. Influence of Elastomer Layers in the Quality of Aluminum Parts on Finishing Operations. Metals 2020, 10, 289 .
AMA StyleAntonio Rubio-Mateos, Asuncion Rivero, Eneko Ukar, Aitzol Lamikiz. Influence of Elastomer Layers in the Quality of Aluminum Parts on Finishing Operations. Metals. 2020; 10 (2):289.
Chicago/Turabian StyleAntonio Rubio-Mateos; Asuncion Rivero; Eneko Ukar; Aitzol Lamikiz. 2020. "Influence of Elastomer Layers in the Quality of Aluminum Parts on Finishing Operations." Metals 10, no. 2: 289.
Dissimilar joining between metal and composite sheets is usually carried out by mechanical or adhesive joining. Laser dissimilar joining between metal and composite sheets could be an alternative to these methods, as it is a cost-effective and versatile joining technique. Previously, textured metallic and composite parts have been held together and heated with a laser beam while pressure is applied to allow the melted polymer to flow into the cavities of the metal part. The main issue of this process relates to reaching the same joint strength repetitively with appropriate process parameters. In this work, both initial texturing and laser joining parameters are studied for Al 7075-T6 and glass-fiber-reinforced PA6 composite. A groove-based geometry was studied in terms of depth-to-width aspect ratio to find an optimal surface using a nanosecond fiber laser for texturing. Laser joining parameters were also studied with different combinations of surface temperature, heating strategy, pressure, and laser feed rate. The results are relatively good for grooves with aspect ratios from 0.94 to 4.15, with the widths of the grooves being the most critical factor. In terms of joining parameters, surface reference temperature was found to be the most influential parameter. Underheating does not allow correct material flow in textured cavities, while overheating also causes high dispersion in the resulting shear strength. When optimal parameters are applied using correct textures, shear strength values over 26 kN are reached, with a contact area of 35 × 45 mm2.
Eneko Ukar; Jon Iñaki Arrizubieta; Mercedes Ferros; Maite Andres; Fernando Liebana. Laser Dissimilar Joining of Al7075T6 with Glass-Fiber-Reinforced Polyamide Composite. Coatings 2020, 10, 96 .
AMA StyleEneko Ukar, Jon Iñaki Arrizubieta, Mercedes Ferros, Maite Andres, Fernando Liebana. Laser Dissimilar Joining of Al7075T6 with Glass-Fiber-Reinforced Polyamide Composite. Coatings. 2020; 10 (2):96.
Chicago/Turabian StyleEneko Ukar; Jon Iñaki Arrizubieta; Mercedes Ferros; Maite Andres; Fernando Liebana. 2020. "Laser Dissimilar Joining of Al7075T6 with Glass-Fiber-Reinforced Polyamide Composite." Coatings 10, no. 2: 96.
Berotako estanpazioan xafla metalikoaren hozketa egokirako hain beharrezkoak diren hozketa-hodiak gaur egun zulaketa bidez fabrikatzea beste irtenbide teknologikorik ez dago. Hala, haien forma fabrikazio-prozesu horrek mugatzen du, eta, hortaz, ezinezkoa da trokelaren gainazal kurboekiko paraleloak diren hozketa-hodiak fabrikatzea. Ondorioz, konformaturiko xaflaren hozketa ez-homogeneoa lortzen da, eta bukaerako piezak propietate mekaniko aldakorrak ditu gune batean eta bestean. Murrizketa horri aurre egiteko helburuarekin, erabaki da hozketa-hodiak laser-ekarpeneko prozesuaren bidez fabrikatzea eta ikerlan honetan prozesu horren bideragarritasuna aztertu da.
Jon Iñaki Arrizubieta; Eneko Ukar; Magdalena Cortina; Jose Exequiel Ruiz; Ines Aseginolaza; Aitzol Lamikiz. Hozketa-hodien fabrikazioa berotako trokeletan laser-ekarpen bidez. EKAIA Euskal Herriko Unibertsitateko Zientzia eta Teknologia Aldizkaria 2019, 71 -94.
AMA StyleJon Iñaki Arrizubieta, Eneko Ukar, Magdalena Cortina, Jose Exequiel Ruiz, Ines Aseginolaza, Aitzol Lamikiz. Hozketa-hodien fabrikazioa berotako trokeletan laser-ekarpen bidez. EKAIA Euskal Herriko Unibertsitateko Zientzia eta Teknologia Aldizkaria. 2019; ():71-94.
Chicago/Turabian StyleJon Iñaki Arrizubieta; Eneko Ukar; Magdalena Cortina; Jose Exequiel Ruiz; Ines Aseginolaza; Aitzol Lamikiz. 2019. "Hozketa-hodien fabrikazioa berotako trokeletan laser-ekarpen bidez." EKAIA Euskal Herriko Unibertsitateko Zientzia eta Teknologia Aldizkaria , no. : 71-94.
Zehaztasunaren ikuspuntutik makina-erreminten diseinuan, eraikuntzan eta martxan jartzean kontuan eduki behar diren puntu garrantzitsuenak bildu dira ikerlan honetan. Horregatik, artikulu honetan, makina-erremintaren diseinu-printzipio garrantzitsuenak azaltzen dira. Gainera, makina-erremintetan ager daitezkeen erroreen ondoriozko ziurgabetasuna zenbatesteko gaur egun gehien erabiltzen den metodoan sakontzen da: errore-aurrekontua. Are gehiago, diseinu egokirako kontuan hartu behar diren printzipioak deskribatzen dira. Azkenik, makina-erreminta muntatu ostean, haren zehaztasuna zenbatesteko existitzen diren nazioarteko arau garrantzitsuenak aztertu dira.
Jon Iñaki Arrizubieta; Ainhoa Celaya; Eneko Ukar; Aitzol Lamikiz. Makina-erreminten errendimendua eta zehaztasuna. EKAIA Euskal Herriko Unibertsitateko Zientzia eta Teknologia Aldizkaria 2019, 9 -30.
AMA StyleJon Iñaki Arrizubieta, Ainhoa Celaya, Eneko Ukar, Aitzol Lamikiz. Makina-erreminten errendimendua eta zehaztasuna. EKAIA Euskal Herriko Unibertsitateko Zientzia eta Teknologia Aldizkaria. 2019; ():9-30.
Chicago/Turabian StyleJon Iñaki Arrizubieta; Ainhoa Celaya; Eneko Ukar; Aitzol Lamikiz. 2019. "Makina-erreminten errendimendua eta zehaztasuna." EKAIA Euskal Herriko Unibertsitateko Zientzia eta Teknologia Aldizkaria , no. : 9-30.
Hybrid machine tools combining additive and subtractive processes have arisen as a solution to increasing manufacture requirements, boosting the potentials of both technologies, while compensating and minimizing their limitations. Nevertheless, the idea of hybrid machines is relatively new and there is a notable lack of knowledge about the implications arisen from their in-practice use. Therefore, the main goal of the present paper is to fill the existing gap, giving an insight into the current advancements and pending tasks of hybrid machines both from an academic and industrial perspective. To that end, the technical-economical potentials and challenges emerging from their use are identified and critically discussed. In addition, the current situation and future perspectives of hybrid machines from the point of view of process planning, monitoring, and inspection are analyzed. On the one hand, it is found that hybrid machines enable a more efficient use of the resources available, as well as the production of previously unattainable complex parts. On the other hand, it is concluded that there are still some technological challenges derived from the interaction of additive and subtractive processes to be overcome (e.g., process planning, decision planning, use of cutting fluids, and need for a post-processing) before a full implantation of hybrid machines is fulfilled.
Magdalena Cortina; Jon Iñaki Arrizubieta; Jose Exequiel Ruiz; Eneko Ukar; Aitzol Lamikiz. Latest Developments in Industrial Hybrid Machine Tools that Combine Additive and Subtractive Operations. Materials 2018, 11, 2583 .
AMA StyleMagdalena Cortina, Jon Iñaki Arrizubieta, Jose Exequiel Ruiz, Eneko Ukar, Aitzol Lamikiz. Latest Developments in Industrial Hybrid Machine Tools that Combine Additive and Subtractive Operations. Materials. 2018; 11 (12):2583.
Chicago/Turabian StyleMagdalena Cortina; Jon Iñaki Arrizubieta; Jose Exequiel Ruiz; Eneko Ukar; Aitzol Lamikiz. 2018. "Latest Developments in Industrial Hybrid Machine Tools that Combine Additive and Subtractive Operations." Materials 11, no. 12: 2583.
The use of hybrid manufacturing processes that combine additive and machining operations is on increase and an example of it is the fact that the most advanced machine tool manufacturers have developed hybrid machines solutions. Nevertheless, cutting fluid required for machining operations can present several problems for the Laser Metal Deposition (LMD) process. In order to solve this issue, the present work evaluates the influence of the coolants in the LMD process from the point of view of pore generation and clad quality. For this purpose, several tests are performed on a part impregnated with cutting fluid, both directly and after the elimination of the fluid by means of different alternatives.
Magdalena Cortina; Jon Iñaki Arrizubieta; Jose Exequiel Ruiz; Eneko Ukar; Aitzol Lamikiz. Study of the porosity generated by the use of cutting fluid in hybrid processes combining machining and Laser Metal Deposition (LMD). Procedia CIRP 2018, 74, 733 -737.
AMA StyleMagdalena Cortina, Jon Iñaki Arrizubieta, Jose Exequiel Ruiz, Eneko Ukar, Aitzol Lamikiz. Study of the porosity generated by the use of cutting fluid in hybrid processes combining machining and Laser Metal Deposition (LMD). Procedia CIRP. 2018; 74 ():733-737.
Chicago/Turabian StyleMagdalena Cortina; Jon Iñaki Arrizubieta; Jose Exequiel Ruiz; Eneko Ukar; Aitzol Lamikiz. 2018. "Study of the porosity generated by the use of cutting fluid in hybrid processes combining machining and Laser Metal Deposition (LMD)." Procedia CIRP 74, no. : 733-737.
A numerical model was developed for predicting the bead geometry and microstructure in laser beam welding of 2 mm thickness Inconel 718 sheets. The experiments were carried out with a 1 kW maximum power fiber laser coupled with a galvanometric scanner. Wobble strategy was employed for sweeping 1 mm wide circular areas for creating the weld seams, and a specific tooling was manufactured for supplying protective argon gas during the welding process. The numerical model takes into account both the laser beam absorption and the melt-pool fluid movement along the bead section, resulting in a weld geometry that depends on the process input parameters, such as feed rate and laser power. The microstructure of the beads was also estimated based on the cooling rate of the material. Features such as bead upper and bottom final shapes, weld penetration, and dendritic arm spacing, were numerically and experimentally analyzed and discussed. The results given by the numerical analysis agree with the tests, making the model a robust predictive tool.
Iñigo Hernando; Jon Iñaki Arrizubieta; Aitzol Lamikiz; Eneko Ukar. Numerical Model for Predicting Bead Geometry and Microstructure in Laser Beam Welding of Inconel 718 Sheets. Metals 2018, 8, 536 .
AMA StyleIñigo Hernando, Jon Iñaki Arrizubieta, Aitzol Lamikiz, Eneko Ukar. Numerical Model for Predicting Bead Geometry and Microstructure in Laser Beam Welding of Inconel 718 Sheets. Metals. 2018; 8 (7):536.
Chicago/Turabian StyleIñigo Hernando; Jon Iñaki Arrizubieta; Aitzol Lamikiz; Eneko Ukar. 2018. "Numerical Model for Predicting Bead Geometry and Microstructure in Laser Beam Welding of Inconel 718 Sheets." Metals 8, no. 7: 536.
A numerical model was developed for predicting the bead geometry and microstructure in Laser Beam Welding of 2 mm thickness Inconel 718 sheets. The experiments were carried out with a 1 kW maximum power fiber laser coupled with a galvanometric scanner. Wobble strategy was employed for sweeping 1 mm wide circular areas for creating the weld seams and a specific tooling was manufactured for supplying protective Argon gas during the welding process. The numerical model takes into account both the laser beam absorption and the melt-pool fluid movement along the bead section, resulting in a weld geometry that depends on the process input parameters, such as feed rate and laser power. The microstructure of the beads was also estimated based on the cooling rate of the material. Features as bead upper and bottom final shapes, weld penetration and dendritic arm spacing were numerically and experimentally analyzed and discussed. The results given by the numerical analysis agree with the tests, making the model a robust predictive tool.
Inigo Hernando; Jon Iñaki Arrizubieta; Aitzol Lamikiz; Eneko Ukar. Numerical Model for Predicting Bead Geometry and Microstructure in Laser Beam Welding of Inconel 718 Sheets. 2018, 1 .
AMA StyleInigo Hernando, Jon Iñaki Arrizubieta, Aitzol Lamikiz, Eneko Ukar. Numerical Model for Predicting Bead Geometry and Microstructure in Laser Beam Welding of Inconel 718 Sheets. . 2018; ():1.
Chicago/Turabian StyleInigo Hernando; Jon Iñaki Arrizubieta; Aitzol Lamikiz; Eneko Ukar. 2018. "Numerical Model for Predicting Bead Geometry and Microstructure in Laser Beam Welding of Inconel 718 Sheets." , no. : 1.
Hybrid manufacturing processes that combine additive and machining operations are gaining relevance in modern industry thanks to the capability of building complex parts with minimal material and, many times, with process time reduction. Besides, as the additive and subtractive operations are carried out in the same machine, without moving the part, dead times are reduced and higher accuracies are achieved. However, it is not clear whether the direct material deposition after the machining operation is possible or intermediate cleaning stages are required because of the possible presence of residual cutting fluids. Therefore, different Laser Metal Deposition (LMD) tests are performed on a part impregnated with cutting fluid, both directly and after the removal of the coolant by techniques such as laser vaporizing and air blasting. The present work studies the influence of the cutting fluid in the LMD process and the quality of the resulting part. Resulting porosity is evaluated and it is concluded that if the part surface is not properly clean after the machining operation, deficient clad quality can be obtained in the subsequent laser additive operation.
Magdalena Cortina; Jon Iñaki Arrizubieta; Eneko Ukar; Aitzol Lamikiz. Analysis of the Influence of the Use of Cutting Fluid in Hybrid Processes of Machining and Laser Metal Deposition (LMD). Coatings 2018, 8, 61 .
AMA StyleMagdalena Cortina, Jon Iñaki Arrizubieta, Eneko Ukar, Aitzol Lamikiz. Analysis of the Influence of the Use of Cutting Fluid in Hybrid Processes of Machining and Laser Metal Deposition (LMD). Coatings. 2018; 8 (2):61.
Chicago/Turabian StyleMagdalena Cortina; Jon Iñaki Arrizubieta; Eneko Ukar; Aitzol Lamikiz. 2018. "Analysis of the Influence of the Use of Cutting Fluid in Hybrid Processes of Machining and Laser Metal Deposition (LMD)." Coatings 8, no. 2: 61.
Hot stamping dies include cooling channels to treat the formed sheet. The optimum cooling channels of dies and molds should adapt to the shape and surface of the dies, so that a homogeneous temperature distribution and cooling are guaranteed. Nevertheless, cooling ducts are conventionally manufactured by deep drilling, attaining straight channels unable to follow the geometry of the tool. Laser Metal Deposition (LMD) is an additive manufacturing technique capable of fabricating nearly free-form integrated cooling channels and therefore shape the so-called conformal cooling. The present work investigates the design and manufacturing of conformal cooling ducts, which are additively built up on hot work steel and then milled in order to attain the final part. Their mechanical performance and heat transfer capability has been evaluated, both experimentally and by means of thermal simulation. Finally, conformal cooling conduits are evaluated and compared to traditional straight channels. The results show that LMD is a proper technology for the generation of cooling ducts, opening the possibility to produce new geometries on dies and molds and, therefore, new products.
Magdalena Cortina; Jon Iñaki Arrizubieta; Amaia Calleja; Eneko Ukar; Amaia Alberdi. Case Study to Illustrate the Potential of Conformal Cooling Channels for Hot Stamping Dies Manufactured Using Hybrid Process of Laser Metal Deposition (LMD) and Milling. Metals 2018, 8, 102 .
AMA StyleMagdalena Cortina, Jon Iñaki Arrizubieta, Amaia Calleja, Eneko Ukar, Amaia Alberdi. Case Study to Illustrate the Potential of Conformal Cooling Channels for Hot Stamping Dies Manufactured Using Hybrid Process of Laser Metal Deposition (LMD) and Milling. Metals. 2018; 8 (2):102.
Chicago/Turabian StyleMagdalena Cortina; Jon Iñaki Arrizubieta; Amaia Calleja; Eneko Ukar; Amaia Alberdi. 2018. "Case Study to Illustrate the Potential of Conformal Cooling Channels for Hot Stamping Dies Manufactured Using Hybrid Process of Laser Metal Deposition (LMD) and Milling." Metals 8, no. 2: 102.
The objective of this work was to select the best material from Fe-, Ni- and Co-based alloy powder for coating, by Laser Metal Deposition (LMD) the filets of a hardened 42CrMoS4 extrusion screw without preheating process. Even though most of the articles recommended preheating the base material as a condition for a crack free coating, the time wasted in the process decrease the productivity and distortions can be also generated in the part. In this work, a comparison of the main characteristics of the coatings done on preheated and non-preheated base material has been made. The relationships between the relevant LMD parameters (feed rate, laser power, and powder feeding rate) and the main geometrical characteristics of a single clad (height, width, dilution, deposition rate, efficiency, etc.) were examined. In addition, different characteristics of overlapped clads in a preheated, non-preheated and a hardened base material have been also analyzed. All the study was made in the Ibarmia ZVH 45/1600 Add+Process hybrid machine with a high power Yb-Fiber laser (3 kW) and discrete coaxial LMD head. Coatings with thickness from 1.2 to 0.76 were created without cracks and other defects except in the case of Ni-based coating. The microstructural features of these coatings were studied using optical and scanning electron microscopy. The mechanical properties were determined using microhardness measurements and a pin on disk tribometer.
Pedro Ramiro; Amaia Alberdi; Mikel Ortiz; Aitzol Lamikiz; Eneko Ukar. Characteristics of Fe-, Ni- and Co-based Powder Coatings Fabricated by Laser Metal Deposition without Preheating the base Material. Procedia CIRP 2018, 68, 381 -386.
AMA StylePedro Ramiro, Amaia Alberdi, Mikel Ortiz, Aitzol Lamikiz, Eneko Ukar. Characteristics of Fe-, Ni- and Co-based Powder Coatings Fabricated by Laser Metal Deposition without Preheating the base Material. Procedia CIRP. 2018; 68 ():381-386.
Chicago/Turabian StylePedro Ramiro; Amaia Alberdi; Mikel Ortiz; Aitzol Lamikiz; Eneko Ukar. 2018. "Characteristics of Fe-, Ni- and Co-based Powder Coatings Fabricated by Laser Metal Deposition without Preheating the base Material." Procedia CIRP 68, no. : 381-386.
Laser Material Deposition (LMD) is a near-net-shape additive process. Powder particles are usually employed as filler material, which is injected through a powder nozzle (coaxial or off-axis) and then completely molten by a laser beam. The possibility to add material on complex 3D surfaces makes LMD a key process in the repair and wear/corrosion protection applications. The present work is focused on the improvement of the design & manufacturing of a LMD nozzle, what introduces two main advantages: the possibility to process a wider variety of materials by generating a protective atmosphere and the improvement of the efficiency of the nozzle. The results of numerical simulations are used for optimizing the design of the protective cone of the LMD nozzle, which is then manufactured and experimentally validated. Finally, the proper performance of the resultant nozzle is tested depositing Ti6Al4 V.
Magdalena Cortina; Jon Iñaki Arrizubieta; Jose Exequiel Ruiz; Aitzol Lamikiz; Eneko Ukar. Design and Manufacturing of a Protective Nozzle for Highly Reactive Materials Processing via Laser Material Deposition. Procedia CIRP 2018, 68, 387 -392.
AMA StyleMagdalena Cortina, Jon Iñaki Arrizubieta, Jose Exequiel Ruiz, Aitzol Lamikiz, Eneko Ukar. Design and Manufacturing of a Protective Nozzle for Highly Reactive Materials Processing via Laser Material Deposition. Procedia CIRP. 2018; 68 ():387-392.
Chicago/Turabian StyleMagdalena Cortina; Jon Iñaki Arrizubieta; Jose Exequiel Ruiz; Aitzol Lamikiz; Eneko Ukar. 2018. "Design and Manufacturing of a Protective Nozzle for Highly Reactive Materials Processing via Laser Material Deposition." Procedia CIRP 68, no. : 387-392.
The melt pool dynamics consideration in the numeric modeling of the Laser Material Deposition (LMD) process can be enormously difficult and expensive, especially if this calculation is not strictly necessary. The increased cost comes mainly from the necessity of considering a higher number of input parameters into the model in addition to the computational cost. Therefore, an analysis of the influence of the melt pool dynamics in a LMD model and its impact on the accuracy is presented. For this purpose, a numeric model that simulates the melt pool fluid-dynamics has been developed and experimentally validated for different situations. After a detailed analysis of the results, an exponential formula based on the response surface methodology (RSM) that quantifies the influence of the fluid-dynamic phenomena inside the melt pool has been obtained. The main conclusion of the present work is that the LMD process can be addresses as a thermal problem without considering the melt pool dynamics and without losing accuracy for a certain window of process parameters, what reduces the computational cost and will allow an easier integration of the model in CAE tools for process simulation
Jon Iñaki Arrizubieta; Aitzol Lamikiz; Fritz Klocke; Silvia Martínez; Kristian Arntz; Eneko Ukar. Evaluation of the relevance of melt pool dynamics in Laser Material Deposition process modeling. International Journal of Heat and Mass Transfer 2017, 115, 80 -91.
AMA StyleJon Iñaki Arrizubieta, Aitzol Lamikiz, Fritz Klocke, Silvia Martínez, Kristian Arntz, Eneko Ukar. Evaluation of the relevance of melt pool dynamics in Laser Material Deposition process modeling. International Journal of Heat and Mass Transfer. 2017; 115 ():80-91.
Chicago/Turabian StyleJon Iñaki Arrizubieta; Aitzol Lamikiz; Fritz Klocke; Silvia Martínez; Kristian Arntz; Eneko Ukar. 2017. "Evaluation of the relevance of melt pool dynamics in Laser Material Deposition process modeling." International Journal of Heat and Mass Transfer 115, no. : 80-91.
Jon Iñaki Arrizubieta; Silvia Martínez; Aitzol Lamikiz; Eneko Ukar; Kristian Arntz; Fritz Klocke. Instantaneous powder flux regulation system for Laser Metal Deposition. Journal of Manufacturing Processes 2017, 29, 242 -251.
AMA StyleJon Iñaki Arrizubieta, Silvia Martínez, Aitzol Lamikiz, Eneko Ukar, Kristian Arntz, Fritz Klocke. Instantaneous powder flux regulation system for Laser Metal Deposition. Journal of Manufacturing Processes. 2017; 29 ():242-251.
Chicago/Turabian StyleJon Iñaki Arrizubieta; Silvia Martínez; Aitzol Lamikiz; Eneko Ukar; Kristian Arntz; Fritz Klocke. 2017. "Instantaneous powder flux regulation system for Laser Metal Deposition." Journal of Manufacturing Processes 29, no. : 242-251.
Silvia Martínez; Aitzol Lamikiz; Eneko Ukar; Ivan Tabernero; Iñaki Arrizubieta. Control loop tuning by thermal simulation applied to the laser transformation hardening with scanning optics process. Applied Thermal Engineering 2016, 98, 49 -60.
AMA StyleSilvia Martínez, Aitzol Lamikiz, Eneko Ukar, Ivan Tabernero, Iñaki Arrizubieta. Control loop tuning by thermal simulation applied to the laser transformation hardening with scanning optics process. Applied Thermal Engineering. 2016; 98 ():49-60.
Chicago/Turabian StyleSilvia Martínez; Aitzol Lamikiz; Eneko Ukar; Ivan Tabernero; Iñaki Arrizubieta. 2016. "Control loop tuning by thermal simulation applied to the laser transformation hardening with scanning optics process." Applied Thermal Engineering 98, no. : 49-60.
The main problem of laser hardening process is the over-tempered structure with a hardness decrement zone in the overlapped area between different laser tracks, which may not meet the minimum hardness requirements. The over-tempered structure is located at the middle of two overlapped laser tracks or between the beginning and the ending of a closed trajectory.In this paper, the hardness in the overlapped zones is studied by means of numerical simulations and experimental tests during a temperature controlled laser hardening with scanning optics process. Thus, in order to study their difference and to validate the proposed methodology, two steels with very different tempering curves has been used; a cold work tool steel and a medium-carbon low-alloy steel
Silvia Martínez; Dmytro Lesyk; Aitzol Lamikiz; Eneko Ukar; Vitaliy Dzhemelinskyi. Hardness Simulation of over-tempered Area During Laser Hardening Treatment. Physics Procedia 2016, 83, 1357 -1366.
AMA StyleSilvia Martínez, Dmytro Lesyk, Aitzol Lamikiz, Eneko Ukar, Vitaliy Dzhemelinskyi. Hardness Simulation of over-tempered Area During Laser Hardening Treatment. Physics Procedia. 2016; 83 ():1357-1366.
Chicago/Turabian StyleSilvia Martínez; Dmytro Lesyk; Aitzol Lamikiz; Eneko Ukar; Vitaliy Dzhemelinskyi. 2016. "Hardness Simulation of over-tempered Area During Laser Hardening Treatment." Physics Procedia 83, no. : 1357-1366.