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Aryal, P. & Choquet, I. (2024). Melt pool electromagnetic force model extended to account for free surface deformation: Application to gas metal arc. International Journal of Heat and Mass Transfer, 221, 124987-124987, Article ID 124987.
Open this publication in new window or tab >>Melt pool electromagnetic force model extended to account for free surface deformation: Application to gas metal arc
2024 (English)In: International Journal of Heat and Mass Transfer, ISSN 0017-9310, E-ISSN 1879-2189, Vol. 221, p. 124987-124987, article id 124987Article in journal (Refereed) Published
Abstract [en]

Computational fluid dynamics models with free surface tracking intended to simulate the melt pool produced by an electric arc usually model the electromagnetic force ignoring the deformation of the free surface. However, with an arc heat source, the electromagnetic force is known to be among the leading-order forces, especially at high currents. In addition, the free surface can undergo significant deformations, especially in the presence of metal transfer. In the present study, a generalization of the electromagnetic force model that accounts for the deformation of the free surface is therefore proposed. Test cases with a pulsed gas-metal arc that transfers one metal drop per pulse were investigated experimentally at three different travel speeds to provide validation data. The cases were simulated with both the proposed and the earlier model to assess the influence of the new developments. The results showed that, in the regions where both models determine the force, the discrepancy between the models’ results can reach up to an order of magnitude. Especially, the earlier model overestimates the electromagnetic force deep into the melt pool. On the other hand, it neglects it in the liquid metal that is located at an elevation above the original upper surface of the workpiece, while the proposed model showed that in this area the intensity of the electromagnetic force is the largest. These significant discrepancies result in non-negligible differences in the predicted melt pool thermal flow and geometry. Especially, the propose dextended model provides an improved prediction of the fingertip-shaped fusion boundary.

Keywords
Self-adapting electromagnetic force model, Frozen electromagnetic force model, Free surface deformation, Molten pool, Gas metal arc
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-21102 (URN)10.1016/j.ijheatmasstransfer.2023.124987 (DOI)
Funder
EU, Horizon Europe, 820776European Commission, 20210094
Note

CC BY 4.0

Available from: 2023-12-20 Created: 2023-12-20 Last updated: 2023-12-20
Noori Rahim Abadi, S. M., Mi, Y., Kisielewicz, A., Sikström, F. & Choquet, I. (2023). Influence of laser-wire interaction on heat and metal transfer in directed energy deposition. International Journal of Heat and Mass Transfer, 205, Article ID 123894.
Open this publication in new window or tab >>Influence of laser-wire interaction on heat and metal transfer in directed energy deposition
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2023 (English)In: International Journal of Heat and Mass Transfer, ISSN 0017-9310, E-ISSN 1879-2189, Vol. 205, article id 123894Article in journal (Refereed) Published
Abstract [en]

In this study, laser metal fusion with feedstock wire is addressed. We investigated how various process parameters affect the fraction of beam energy that is absorbed by the wire and the workpiece and the metal transfer from the feedstock wire to the melt pool. To perform this research, a thermo-fluid dynamic model with tracking of free surface deformation was developed to include the feeding of a solid wire and predict its melting. The fraction of beam energy absorbed by the metal was modeled as a function of local surface curvature and temperature, accounting for multiple Fresnel reflections and absorptions. The model was applied to Titanium alloy (Ti-6Al-4V) with a 1.07 μm laser and a process in conduction mode. Experiments at various wire feeding rates were conducted to evaluate the model’s ability to predict the process and a good agreement was obtained. The different parameters studied were the beam angular position, the wire angular position, the wire feed rate, and the beam-wire offset. The analysis of the simulation results gave a detailed physical understanding of the laser energy use. It highlighted that thermocapillary and Rayleigh-Plateau instabilities can contribute to the transition from continuous to drop metal transfer mode. Damping these instabilities might thus allow using a wider process window.

Keywords
Laser beam, Feedstock wire, Metal fusion, Metal deposition, Energy deposition, Process stability, CFD Simulation
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-20037 (URN)10.1016/j.ijheatmasstransfer.2023.123894 (DOI)000965022600001 ()2-s2.0-85147203744 (Scopus ID)
Funder
Knowledge Foundation, 20170315
Note

 CC BY-NC-ND 

This research work was supported by grants from the Swedish Knowledge Foundation, projects AdOpt (20170315) and SAMw(20170060), which is gratefully acknowledged.

Available from: 2023-06-13 Created: 2023-06-13 Last updated: 2024-01-08Bibliographically approved
Choquet, I. & Zhang, W. (2023). Process modeling of powder bed and directed energy deposition (1.ed.). In: Pederson, Robert, Andersson, Joel & Joshi, Shrikant V. (Ed.), Additive Manufacturing of High-Performance metallic Materials: (pp. 518-611). Elsevier
Open this publication in new window or tab >>Process modeling of powder bed and directed energy deposition
2023 (English)In: Additive Manufacturing of High-Performance metallic Materials / [ed] Pederson, Robert, Andersson, Joel & Joshi, Shrikant V., Elsevier , 2023, 1., p. 518-611Chapter in book (Refereed)
Abstract [en]

Metal additive manufacturing (AM) is used to build and repair metal parts with heat input from a high-power beam (laser or electron beam) or electric arc (gas metal, gas tungsten, or gas plasma arc) and metal deposited layer by layer from powder or wire feedstock. This multiscale and multiphysics process is difficult to directly observe. It's modeling thus contributes to gaining process understanding. It can also support process parameter selection, process control, path planning, modeling and analysis of microstructure, distortion, and residual stress formed during metal AM. The sections of this chapter address first the electron beam, laser beam, and electric arc heat sources including their interaction with metal. Next, it covers process modeling with the thermal and thermo-fluid approaches and metal provided in the form of either powder or wire feedstock. Each of these sections includes a description of the physics taking place, the existing modeling approaches, the related assumptions and framework of application, open questions, as well as examples of knowledge the models provide access to.

Place, publisher, year, edition, pages
Elsevier, 2023 Edition: 1.
Keywords
Electric arc; Electron beam; Heat source; Laser beam; Melt pool; Powder feedstock; Thermal modeling approach; Thermo fluid dynamics approach; Wire feedstock
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-21076 (URN)9780323918855 (ISBN)9780323913829 (ISBN)
Available from: 2023-12-14 Created: 2023-12-14 Last updated: 2024-01-11
Noori Rahim Abadi, S. M., Hagqvist, P., Sikström, F. & Choquet, I. (2022). CFD-Based Feasibility Study of Laser-Directed Energy Deposition With a Metal Wire for On-Orbit Manufacturing. Frontiers in Space Technologies, 3, 1-13, Article ID 880012.
Open this publication in new window or tab >>CFD-Based Feasibility Study of Laser-Directed Energy Deposition With a Metal Wire for On-Orbit Manufacturing
2022 (English)In: Frontiers in Space Technologies, E-ISSN 2673-5075, Vol. 3, p. 1-13, article id 880012Article in journal (Refereed) Published
Abstract [en]

Additive manufacturing of parts on-site in space requires investigating the feasibility ofadapting to zero-gravity and near-vacuum conditions, a technology applied today on Earthat standard conditions. While a few studies have been conducted for powder bed fusion, afeasibility study remains to be explored for direct energy deposition using a laser beam anda metal wire. This is the purpose of this study, which is conducted using a modelingapproach based on computational fluid dynamics. The simulation model developedincludes melting, re-solidification, vaporization, prediction of beam energy absorptionas a function of the local surface temperature and curvature, ray tracing, tracking of freesurface deformation and metal transfer, and wire-resistive heating. The study is carried outby starting from process parameters suited for stable on-Earth metal deposition. Theseconditions were also studied experimentally to validate the simulation model, leading tosatisfactorily results. A total of three other test cases with ambient pressure lowered downto near-vacuum and/or gravitation down to zero are investigated. It is found that,compared to on-Earth conditions, in-space conditions can induce vaporization of themetal alloy that is large enough to result in a curvature of the melt pool free surface but toosmall to lead to the formation of a keyhole. The in-space conditions can also modify theforce balance at the liquid melt bridge between the wire and the melt pool, leading to smallchanges in the curvature and temperature field at the free surface of the wire tip. Among theobserved consequences are a small increase of the melt pool length and a small elevationof the bead height. More importantly, for process control, changing to in-space conditionsmight also affect the stability of the process, which could be assessed through the width ofthe liquid metal bridge. However, by using appropriate process control to maintain acontinuous liquid metal bridge, it is concluded that direct energy deposition of metal usinga laser and a wire could be used for manufacturing metal parts in-space in a temperedatmosphere.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2022
Keywords
LDEDw, ambient pressure, gravity, metal deposition, melt pool simulation, OpenFOAM
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-19031 (URN)10.3389/frspt.2022.880012 (DOI)
Note

This research work is supported by grants from the SwedishKnowledge Foundation projects AdOpt (20170315) and SAMw(20170060), which is gratefully acknowledged.

Available from: 2022-08-10 Created: 2022-08-10 Last updated: 2023-03-15Bibliographically approved
Aryal, P., Sikström, F., Nilsson, H. & Choquet, I. (2022). Comparative study of the main electromagnetic models applied to melt pool prediction with gas metal arc: Effect on flow, ripples from drop impact, and geometry. International Journal of Heat and Mass Transfer, 194, Article ID 123068.
Open this publication in new window or tab >>Comparative study of the main electromagnetic models applied to melt pool prediction with gas metal arc: Effect on flow, ripples from drop impact, and geometry
2022 (English)In: International Journal of Heat and Mass Transfer, ISSN 0017-9310, E-ISSN 1879-2189, Vol. 194, article id 123068Article in journal (Refereed) Published
Abstract [en]

The present work concerns the electromagnetic force models in computational fluid dynamics simulations of melt pools produced with electric arcs. These are commonly applied to gas metal arcs with metal transfer, in welding and additive manufacturing. Metal drop impact on the melt pool is thus included in this study. The electromagnetic force models applied in literature use either numerical solutions of Poisson equations or one of the two analytical models developed by Kou and Sun, or Tsao and Wu. These models rely on assumptions for which the effect on the melt pool predictions remains to be understood. The present work thoroughly investigates those assumptions and their effects. It has been supported by dedicated experimental tests that did provide estimates of unknown model parameters and validation data. The obtained results show that the assumptions that fundamentally distinguish these three models change the electromagnetic force, including the relation between its components. These changes, which can also be spatially non-uniform, are large. As a result, these models lead to significantly different recirculation flow pattern, thermal convection, melt pool morphology, bead dimensions, and free surface response to the metal transfer. We conclude by proposing conditions in which each of these models is suited or questionable.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Maxwell electromagnetic force model, Kou and Sun model, Tsao and Wu model, Metal transfer, Molten pool, Free surface oscillation, Gas metal arc
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-19030 (URN)10.1016/j.ijheatmasstransfer.2022.123068 (DOI)
Funder
European CommissionEU, Horizon Europe
Note

CC BY-NC-ND license

Available from: 2022-08-10 Created: 2022-08-10 Last updated: 2023-08-31Bibliographically approved
Mi, Y., Mahade, S., Sikström, F., Choquet, I., Joshi, S. V. & Ancona, A. (2022). Conduction mode laser welding with beam shaping using a deformable mirror. Optics and Laser Technology, 148
Open this publication in new window or tab >>Conduction mode laser welding with beam shaping using a deformable mirror
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2022 (English)In: Optics and Laser Technology, ISSN 0030-3992, E-ISSN 1879-2545, Vol. 148Article in journal (Refereed) Published
Abstract [en]

This study explores the possibility of tailoring the fusion zone in conduction mode laser welding using a deformable mirror for beam shaping of multi-kilowatt continuous wave laser sources. Three power density distributions were shaped and used in bead on plate welding of Ti64 plates in conduction mode at three travel speeds. The effect on melt pool free surface geometry, cross section, microstructure and hardness profiles was measured and studied. It is shown that the geometry of the melt pool can be modified using a deformable mirror. A narrower and longer melt pool or a wider, shorter and shallower one were indeed obtained forming Gaussian-elliptical power density distributions oriented along and transverse to the travel direction, respectively. The latter distribution could be a favourable option for laser beam additive manufacturing as it could improve process efficiency while reducing remelting of the previous layer. This system has also a promising potential for adaptive process control since it could change fundamentally the beam shape at a rate faster than 10 ms. 

Place, publisher, year, edition, pages
Elsevier Ltd, 2022
Keywords
Adaptive control systems; Continuous wave lasers; Deformation; Gaussian beams; Lakes; Laser beam welding; Laser beams; Laser mirrors; Microstructure, Beam-shaping; Conduction mode; Conduction mode laser welding; Conduction mode welding; Deformable mirrors; Fusion zone geometry; Fusion zones; Melt pool; Melt pool geometry; Power density distributions, Geometry
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-17945 (URN)10.1016/j.optlastec.2021.107718 (DOI)2-s2.0-85120819958 (Scopus ID)
Funder
Knowledge Foundation, 20170315
Available from: 2022-03-07 Created: 2022-03-07 Last updated: 2022-03-31
Noori Rahim Abadi, S. M., Mi, Y., Sikström, F., Ancona, A. & Choquet, I. (2021). Effect of shaped laser beam profiles on melt flow dynamics in conduction mode welding. International journal of thermal sciences, 166, 1-15, Article ID 106957.
Open this publication in new window or tab >>Effect of shaped laser beam profiles on melt flow dynamics in conduction mode welding
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2021 (English)In: International journal of thermal sciences, ISSN 1290-0729, E-ISSN 1778-4166, Vol. 166, p. 1-15, article id 106957Article in journal (Refereed) Published
Abstract [en]

A computational fluid dynamics approach is used to analyse the influence of beam shaping in fusion welding on melt thermal flow. Three beam shapes are studied at several welding travel speeds: a reference Gaussian profile and its elliptic elongations along and transverse to the welding travel direction. It is found that these beam shapes change not only the intensity and direction of the melt thermocapillary flow but also the flow pattern. For instance, and contrary to the other profiles, the beam shape elongated along the welding travel direction generates melt front vortices that assist metal pre-heating. It can result in deeper penetration, larger melt volume, and lower amount of thermal energy diffused into the heat affected zone. The simple elongation of a beam profile has thus a non-linear effect on the melt flow and in turn on the seam geometry as well as the temperature gradients in the heat affected zone.

Keywords
Laser beam welding, Beam shaping, Phase change, Melt flow, Free surface deformation
National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:hv:diva-17409 (URN)10.1016/j.ijthermalsci.2021.106957 (DOI)000645187000002 ()2-s2.0-85103695215 (Scopus ID)
Available from: 2021-09-01 Created: 2021-09-01 Last updated: 2023-01-05Bibliographically approved
Aryal, P., Hurtig, K., Sikström, F., Nilsson, H. & Choquet, I. (2021). Effect of Substrate Orientation on Melt Pool during Multi-Layer Deposition in V-Groove with Gas Metal Arc. In: Huihe Qiu (Ed.), Proceedings of the 7th World Congress on Mechanical, Chemical, and Material Engineering (MCM'21): . Paper presented at 7th World Congress on Mechanical, Chemical, and Material Engineering (MCM'21). , Article ID HTFF 130.
Open this publication in new window or tab >>Effect of Substrate Orientation on Melt Pool during Multi-Layer Deposition in V-Groove with Gas Metal Arc
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2021 (English)In: Proceedings of the 7th World Congress on Mechanical, Chemical, and Material Engineering (MCM'21) / [ed] Huihe Qiu, 2021, article id HTFF 130Conference paper, Published paper (Refereed)
Abstract [en]

Thermo-fluid dynamic and experimental approaches are used to investigate the influence of 20° uphill, downhill and sideway substrate orientation during metal deposition over a previously deposited bead in a V-groove. The computational fluid dynamic model with free surface deformation and metal transfer gives insight into the melt pool flow and causes of defect formation observed on the solidified beads. The experimental metallographs, high-speed images and computational results show good agreement. It is found that the deposition of a second layer on a smooth first layer cooled down to room temperature leads to large changes in melt pool flow patternat 20° substrate inclination compared to flat condition. It results in undercut and humps with the uphill orientation and undercut with the side inclination. Therefore, lower angle range is necessary for multilayer gas metal arc deposition for these two last configurations.

Keywords
metal deposition, gas metal arc welding, V-groove, substrate orientation, melt flow, reinforced bead, hump, OpenFOAM
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-17668 (URN)10.11159/htff21.130 (DOI)978-1-927877-93-7 (ISBN)
Conference
7th World Congress on Mechanical, Chemical, and Material Engineering (MCM'21)
Funder
EU, Horizon 2020, INTEGRADDESwedish National Infrastructure for Computing (SNIC)
Available from: 2021-11-01 Created: 2021-11-01 Last updated: 2023-08-31Bibliographically approved
Noori Rahim Abadi, S. M., Mi, Y., Sikström, F. & Choquet, I. (2021). Modelling of beam energy absorbed locally in conduction mode laser metal fusion. Journal of physics. D, Applied physics, 55(2), Article ID 025301.
Open this publication in new window or tab >>Modelling of beam energy absorbed locally in conduction mode laser metal fusion
2021 (English)In: Journal of physics. D, Applied physics, ISSN 0022-3727, Vol. 55, no 2, article id 025301Article in journal (Refereed) Published
Abstract [en]

Fluid dynamics models for laser material processing with metal fusion in conduction mode generally assume a constant absorptivity. This parameter is known to govern the process. However, it used to be pre-set by extrapolating absorptance measurements made at different conditions or adjusted to reproduce experimental bead shapes. In this study a new approach isd eveloped. It consists in predicting the absorptance as a function of local surface conditions, including the surface temperature. The proposed absorptance model is applied to the metal alloyTi-6Al-4V. It is found that the absorptance of this alloy changes with surface temperature over awide range of beam incidence angles. Thermo-fluid simulations with tracking of the free-surface deformation are performed for conduction mode beam welding test cases with a Yb fibre laser and different travel speeds. It is found that the absorptivity coefficient commonly used for this process clearly underestimates the absorptance and the melt pool geometry predicted for the process conditions of this study. The computational results are also compared against experimental results and good quantitative agreement of the melt pool depth, width, length, free surface contour geometry, and the curvature of the end depression left afterre-solidification at the laser switch-off location is obtained. The results show that the absorptance field predicted depends on the melt pool development stage, on the spatial location within the beam spot, and on the process conditions.

Place, publisher, year, edition, pages
Bristol: IOP Publishing, 2021
Keywords
Surfaces, Coatings and Films, Acoustics and Ultrasonics, Condensed Matter Physics, Electronic, Optical and Magnetic Materials
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-17583 (URN)10.1088/1361-6463/ac296a (DOI)2-s2.0-85117731214 (Scopus ID)
Funder
Knowledge Foundation
Available from: 2021-10-19 Created: 2021-10-19 Last updated: 2022-10-10
Noori Rahim Abadi, S. M., Mi, Y., Sikström, F. & Choquet, I. (2020). Influence of Laser Beam Shaping on Melt Pool Thermocapillary Flow. In: Huihe Qiu (Ed.), Proceedings of the 6th World Congress on Mechanical, Chemical, and Material Engineering (MCM'20) Prague, Czech Republic Virtual Conference – August, 2020: . Paper presented at 6th World Congress on Mechanical, Chemical, and Material Engineering (MCM'20) Prague, Czech Republic Virtual Conference – August, 2020. , Article ID HTFF 125.
Open this publication in new window or tab >>Influence of Laser Beam Shaping on Melt Pool Thermocapillary Flow
2020 (English)In: Proceedings of the 6th World Congress on Mechanical, Chemical, and Material Engineering (MCM'20) Prague, Czech Republic Virtual Conference – August, 2020 / [ed] Huihe Qiu, 2020, article id HTFF 125Conference paper, Published paper (Refereed)
Abstract [en]

The effect of different shapes of laser beam power density distribution was investigated numerically with respect to the thermo-hydrodynamics of the melt pool during welding. The process addressed is conduction mode bead on plate welding of the Titanium alloy Ti-6Al-4V. A new solver based on the volume of fluid method to track the deformation of the melt free surface was developed in the OpenFOAM software. Experiments were conducted for the purpose of validating the model. In addition to the traditional cross-cut images of the weld bead, top view images of the melt pool were analysed to perform the validation along the 3-space dimensions. A good agreement between numerical predictions and experimental measurements was obtained, thus promising aconfident utilization of this simulation model when investigating the influence of beam shapes on the resulting weld seam. The effectof three different beam shapes on the melt pool velocity flow, temperature fields, and melt geometry were studied. It was found that the melt pool size was largest for an elliptical power density distribution with the major axis along the welding direction. The results also showed that the laser beam with Gaussian power density distribution resulted in the deepest penetration.

Keywords
Thermocapillary Flow, Free surface deformation, Laser beam shaping, Welding, VOF, Open FOAM, Validation
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-16104 (URN)10.11159/htff20.125 (DOI)
Conference
6th World Congress on Mechanical, Chemical, and Material Engineering (MCM'20) Prague, Czech Republic Virtual Conference – August, 2020
Note

Swedish Knowledge Foundation projects AdOpt (20170315) and SAMw (20170060)

Available from: 2020-12-09 Created: 2020-12-09 Last updated: 2021-09-01Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-2535-8132

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