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Mi, Y., Guglielmi, P., Nilsen, M., Sikström, F., Palumbo, G. & Ancona, A. (2023). Beam shaping with a deformable mirror for gap bridging in autogenous laser butt welding. Optics and Lasers in Engineering, 169, Article ID 107724.
Öppna denna publikation i ny flik eller fönster >>Beam shaping with a deformable mirror for gap bridging in autogenous laser butt welding
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2023 (Engelska)Ingår i: Optics and Lasers in Engineering, ISSN 0143-8166, Vol. 169, artikel-id 107724Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

In autogenous laser butt welding the variability of the joint gap can cause problems in terms of weld seam quality. A suitable strategy to alleviate this is to dynamically shape the laser beam instead of a circular-shaped beam with typical Gaussian or top hat distributions. Currently available systems cannot reach sufficient performance due to both the real time control system for the shape variation and the limited laser power currently manageable. In the present work, the possibility of bridging the joint gap during welding using a deformable mirror to elongate the focused laser beam from circular to transversal elliptical shape was investigated. The effect of the beam shaping on the geometry of the weld pool and of the weld cross sections was analysed, for different values of the gap in comparison with a circular Gaussian beam. It was demonstrated that the adoption of a transversal elliptical laser beam makes the welding process more stable, especially for large gaps (i.e. larger than the circular beam radius). Thanks to the beam shaping, the extension of the fused zone (in terms of the cross section area, height and width) resulted to be less sensitive to the gap's dimension; in addition, the extension of the heat affected zone and the presence of undercuts were evidently reduced.

Nyckelord
Laser beam welding, Beam shaping, Process monitoring, Microstructure, Steel
Nationell ämneskategori
Bearbetnings-, yt- och fogningsteknik
Forskningsämne
Produktionsteknik
Identifikatorer
urn:nbn:se:hv:diva-20684 (URN)10.1016/j.optlaseng.2023.107724 (DOI)001041329900001 ()2-s2.0-85164226707 (Scopus ID)
Forskningsfinansiär
KK-stiftelsen, 20170315KK-stiftelsen, 20210094
Tillgänglig från: 2023-12-29 Skapad: 2023-12-29 Senast uppdaterad: 2024-03-15Bibliografiskt granskad
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.
Öppna denna publikation i ny flik eller fönster >>Influence of laser-wire interaction on heat and metal transfer in directed energy deposition
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2023 (Engelska)Ingår i: International Journal of Heat and Mass Transfer, ISSN 0017-9310, E-ISSN 1879-2189, Vol. 205, artikel-id 123894Artikel i tidskrift (Refereegranskat) 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.

Nyckelord
Laser beam, Feedstock wire, Metal fusion, Metal deposition, Energy deposition, Process stability, CFD Simulation
Nationell ämneskategori
Bearbetnings-, yt- och fogningsteknik
Forskningsämne
Produktionsteknik
Identifikatorer
urn:nbn:se:hv:diva-20037 (URN)10.1016/j.ijheatmasstransfer.2023.123894 (DOI)000965022600001 ()2-s2.0-85147203744 (Scopus ID)
Forskningsfinansiär
KK-stiftelsen, 20170315
Anmärkning

 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.

Tillgänglig från: 2023-06-13 Skapad: 2023-06-13 Senast uppdaterad: 2024-01-08Bibliografiskt granskad
Ancona, A., Sikström, F., Christiansson, A.-K., Nilsen, M., Mi, Y. & Kisielewicz, A. (2023). Monitoring and control of directed energy deposition using a laser beam (1.ed.). In: Pederson, Robert, Andersson, Joel & Joshi, Shrikant V. (Ed.), Additive Manufacturing of High-Performance metallic Materials: (pp. 612-638). Elsevier
Öppna denna publikation i ny flik eller fönster >>Monitoring and control of directed energy deposition using a laser beam
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2023 (Engelska)Ingår i: Additive Manufacturing of High-Performance metallic Materials / [ed] Pederson, Robert, Andersson, Joel & Joshi, Shrikant V., Elsevier, 2023, 1., s. 612-638Kapitel i bok, del av antologi (Refereegranskat)
Abstract [en]

To be a successful competitor among other technologies, metallic laser-directed energy depositionusing a laser beam would benefit from the support of intelligent automation making the processrobust, repeatable, and cost-efficient. This calls for technology leaps towards robust and accuratedetection and estimation of the conditions during processing and control schemes for robustperformance. This chapter discusses how developments in sensor technology and model-basedsignal processing can contribute to advancements in in-process monitoring of directed energydeposition using a laser beam and how developments in model-based feedforward- and feedbackcontrol can support automation. The focus is on how machine vision, optical emission spectroscopy,thermal sensing, and electrical process signals can support monitoring, control and better processunderstanding. These approaches are industrially relevant and have a high potential to support amore sustainable manufacturing. 

Ort, förlag, år, upplaga, sidor
Elsevier, 2023 Upplaga: 1.
Nyckelord
Directed energy deposition using a laser beam; Electrical process signals; Feedstock wire and powder; Infrared imaging; Machine vision; Model-based control; Photo detection; Radiation pyrometry; Signal processing; Spectroscopy
Nationell ämneskategori
Bearbetnings-, yt- och fogningsteknik
Forskningsämne
Produktionsteknik
Identifikatorer
urn:nbn:se:hv:diva-21079 (URN)9780323918855 (ISBN)9780323913829 (ISBN)
Tillgänglig från: 2023-12-14 Skapad: 2023-12-14 Senast uppdaterad: 2024-01-11Bibliografiskt granskad
Kisielewicz, A., Mi, Y., Sikström, F. & Ancona, A. (2023). Multi sensor monitoring  of the wire-melt pool interaction inhot-wire directed energy deposition using laser beam. In: IOP Conference Series: Materials Science and Engineering. Paper presented at NOLAMP 19th Nordic Laser Material Processing Conference 22-24 August 2023 Turku, Finland (pp. 1-11). IOP Publishing, 1296, Article ID 012011.
Öppna denna publikation i ny flik eller fönster >>Multi sensor monitoring  of the wire-melt pool interaction inhot-wire directed energy deposition using laser beam
2023 (Engelska)Ingår i: IOP Conference Series: Materials Science and Engineering, IOP Publishing , 2023, Vol. 1296, s. 1-11, artikel-id 012011Konferensbidrag, Muntlig presentation med publicerat abstract (Refereegranskat)
Abstract [en]

This study investigates the combination of three sensors to improve in-process monitoring of the liquid bridge between the feedstock wire and melt pool in hot-wire Directed Energy Deposition using Laser Beam. The stability of the deposition process relies on the transfer of metal between the molten feedstock wire and melt pool. Therefore, monitoring the condition of the liquid bridge and the interaction between the feedstock wire and melt pool is crucial. By utilizing a laser-optics-integrated visible range optical spectrometer and electrical sensors measuring voltage and current, relevant process changes and indications of instabilities were detected. Combined information from the current sensor and the spectrometer provided a better understanding of the process and helped to identify deviations leading to unstable deposition modes.

Ort, förlag, år, upplaga, sidor
IOP Publishing, 2023
Nyckelord
wire-melt, laser beam, multi sensor monitoring
Nationell ämneskategori
Bearbetnings-, yt- och fogningsteknik
Forskningsämne
Produktionsteknik
Identifikatorer
urn:nbn:se:hv:diva-20863 (URN)10.1088/1757-899X/1296/1/012011 (DOI)
Konferens
NOLAMP 19th Nordic Laser Material Processing Conference 22-24 August 2023 Turku, Finland
Forskningsfinansiär
Vetenskapsrådet, SAMw [20170060]Vinnova, InAIRwire [2019-02752]
Anmärkning

CC BY 3.0

Tillgänglig från: 2024-02-15 Skapad: 2024-02-15 Senast uppdaterad: 2024-02-15
Jadidi, A., Mi, Y., Sikström, F., Nilsen, M. & Ancona, A. (2022). Beam Offset Detection in Laser Stake Welding of Tee Joints Using Machine Learning and Spectrometer Measurements. Sensors, 22(10)
Öppna denna publikation i ny flik eller fönster >>Beam Offset Detection in Laser Stake Welding of Tee Joints Using Machine Learning and Spectrometer Measurements
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2022 (Engelska)Ingår i: Sensors, E-ISSN 1424-8220, Vol. 22, nr 10Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Laser beam welding offers high productivity and relatively low heat input and is one key enabler for efficient manufacturing of sandwich constructions. However, the process is sensitive to how the laser beam is positioned with regards to the joint, and even a small deviation of the laser beam from the correct joint position (beam offset) can cause severe defects in the produced part. With tee joints, the joint is not visible from top side, therefore traditional seam tracking methods are not applicable since they rely on visual information of the joint. Hence, there is a need for a monitoring system that can give early detection of beam offsets and stop the process to avoid defects and reduce scrap. In this paper, a monitoring system using a spectrometer is suggested and the aim is to find correlations between the spectral emissions from the process and beam offsets. The spectrometer produces high dimensional data and it is not obvious how this is related to the beam offsets. A machine learning approach is therefore suggested to find these correlations. A multi-layer perceptron neural network (MLPNN), support vector machine (SVM), learning vector quantization (LVQ), logistic regression (LR), decision tree (DT) and random forest (RF) were evaluated as classifiers. Feature selection by using random forest and non-dominated sorting genetic algorithm II (NSGAII) was applied before feeding the data to the classifiers and the obtained results of the classifiers are compared subsequently. After testing different offsets, an accuracy of 94% was achieved for real-time detection of the laser beam deviations greater than 0.9 mm from the joint center-line.

Ort, förlag, år, upplaga, sidor
MDPI, 2022
Nyckelord
laser beam offset; feature selection; laser beam welding; machine learning; spectrometer; tee joint
Nationell ämneskategori
Bioinformatik och systembiologi
Forskningsämne
Produktionsteknik
Identifikatorer
urn:nbn:se:hv:diva-18671 (URN)10.3390/s22103881 (DOI)000803647200001 ()35632290 (PubMedID)2-s2.0-85130378549 (Scopus ID)
Forskningsfinansiär
KK-stiftelsen, 20170315
Tillgänglig från: 2022-06-28 Skapad: 2022-06-28 Senast uppdaterad: 2024-04-12
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
Öppna denna publikation i ny flik eller fönster >>Conduction mode laser welding with beam shaping using a deformable mirror
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2022 (Engelska)Ingår i: Optics and Laser Technology, ISSN 0030-3992, E-ISSN 1879-2545, Vol. 148Artikel i tidskrift (Refereegranskat) 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. 

Ort, förlag, år, upplaga, sidor
Elsevier Ltd, 2022
Nyckelord
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
Nationell ämneskategori
Bearbetnings-, yt- och fogningsteknik
Forskningsämne
Produktionsteknik
Identifikatorer
urn:nbn:se:hv:diva-17945 (URN)10.1016/j.optlastec.2021.107718 (DOI)000788245300001 ()2-s2.0-85120819958 (Scopus ID)
Forskningsfinansiär
KK-stiftelsen, 20170315
Tillgänglig från: 2022-03-07 Skapad: 2022-03-07 Senast uppdaterad: 2024-04-12
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.
Öppna denna publikation i ny flik eller fönster >>Effect of shaped laser beam profiles on melt flow dynamics in conduction mode welding
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2021 (Engelska)Ingår i: International journal of thermal sciences, ISSN 1290-0729, E-ISSN 1778-4166, Vol. 166, s. 1-15, artikel-id 106957Artikel i tidskrift (Refereegranskat) 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.

Nyckelord
Laser beam welding, Beam shaping, Phase change, Melt flow, Free surface deformation
Nationell ämneskategori
Bearbetnings-, yt- och fogningsteknik
Identifikatorer
urn:nbn:se:hv:diva-17409 (URN)10.1016/j.ijthermalsci.2021.106957 (DOI)000645187000002 ()2-s2.0-85103695215 (Scopus ID)
Tillgänglig från: 2021-09-01 Skapad: 2021-09-01 Senast uppdaterad: 2023-01-05Bibliografiskt granskad
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.
Öppna denna publikation i ny flik eller fönster >>Modelling of beam energy absorbed locally in conduction mode laser metal fusion
2021 (Engelska)Ingår i: Journal of physics. D, Applied physics, ISSN 0022-3727, Vol. 55, nr 2, artikel-id 025301Artikel i tidskrift (Refereegranskat) 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.

Ort, förlag, år, upplaga, sidor
Bristol: IOP Publishing, 2021
Nyckelord
Surfaces, Coatings and Films, Acoustics and Ultrasonics, Condensed Matter Physics, Electronic, Optical and Magnetic Materials
Nationell ämneskategori
Bearbetnings-, yt- och fogningsteknik
Forskningsämne
Produktionsteknik
Identifikatorer
urn:nbn:se:hv:diva-17583 (URN)10.1088/1361-6463/ac296a (DOI)2-s2.0-85117731214 (Scopus ID)
Forskningsfinansiär
KK-stiftelsen
Tillgänglig från: 2021-10-19 Skapad: 2021-10-19 Senast uppdaterad: 2022-10-10
Mi, Y. (2021). Novel beam shaping and computer vision methods for laser beam welding. (Licentiate dissertation). Trollhättan: University West
Öppna denna publikation i ny flik eller fönster >>Novel beam shaping and computer vision methods for laser beam welding
2021 (Engelska)Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

Laser beam welding has been widely applied in different industrial sectors due to its unique advantages. However, there are still challenges, such as beam positioning in T-joint welding, and gap bridging in butt joint welding,especially in the case of varying gap width along a joint. It is expected that enabling more advanced control to a welding system, and obtaining more in-depth process knowledge could help to solve these issues. The aim of this work is to address such welding issues by a laser beam shaping technology using a novel deformable mirror together with computer vision methods and also to increase knowledge about the benefits and limitations with this approach.

Beam shaping in this work was realized by a novel deformable mirror system integrated into an industrial processing optics. Together with a wave front sensor, a controlled adaptive beam shaping system was formed with a response time of 10 ms. The processes were monitored by a coaxial camera with selected filters and passive or active illumination. Conduction mode autogenous bead-on-plate welding and butt joint welding experiments have been used to understand the effect of beam shaping on the melt pool geometry. Circular Gaussian, and elliptical Gaussian shapes elongated transverse to and along the welding direction were studied. In-process melt pool images and cross section micrographs of the weld seams/beads were analyzed. The results showed that the melt pool geometry can be significantly modified by beam shaping using the deformable mirror. T-joint welding with different beam offset deviations relative to the center of the joint line was conducted to study the potential of using machine learning to track the process state. The results showed that machine learning can reach sufficient detection and estimation performance, which could also be used for on-line control. In addition, in-process and multidimensional data were accurately acquired using computer vision methods. These data reveal weaknesses of current thermo-fluid simulation model, which in turn can help to better understand and control laser beam welding. The obtained results in this work shows a huge potential in using the proposed methods to solve relevant challenges in laser beam welding.

Abstract [sv]

Lasersvetsning används i stor utsträckning i olika industrisektorer på grund av dess unika fördelar. Det finns emellertid fortfarande utmaningar, såsom rätt positionering av laserstrålen vid genomträngningssvetsning av T-fogar och hantering av varierande spaltbredd längs fogen vid svetsning av stumfogar. Sådana problem förväntas kunna lösas med avancerade metoder för automatisering, metoder som också förväntas ge fördjupade kunskaper om processen. Syftet med detta arbete är att ta itu med dessa problem med hjälp av en teknik för lasereffektens fördelning på arbetsstycket, s.k. beam shaping. Det sker med hjälp av en ny typ av i realtid deformerbar spegel tillsammans med bildbehandling av kamerabilder från processen. För- och nackdelar med detta tillvägagångssätt undersöks.Beam shaping åstadkoms med hjälp av ny typ av deformerbart spegelsystem som integreras i en industriell processoptik. Tillsammans med en vågfrontsensor bildas ett adaptivt system för beam shaping med en svarstid på 10 ms. Processen övervakas av en kamera linjerad koaxialt med laserstrålen. För att kunna ta bilder av svetspunkten belyses den med ljus av lämplig våglängd, och kameran är försedd med ett motsvarande optiskt filter. Försök har utförts med svetsning utan tillsatsmaterial, direkt på plåtar, svetsning utan s.k. nyckelhål, för att förstå effekten av beam shaping på svetssmältans geometri. Gauss fördelade cirkulära och elliptiska former, långsträckta både tvärs och längs svetsriktningen har studerats. Bilder från svetssmältan har analyserats och även mikrostrukturen i tvärsnitt från de svetsade plåtarna. Resultaten visar att svetssmältans geometri kan modifieras signifikant genom beam shaping med hjälp av det deformerbara spegelsystemet. Genomträngningssvetsning av T-fogar med avvikelser relativt foglinjens centrum genomfördes för att studera potentialen i att använda maskininlärning för att fånga processens tillstånd. Resultaten visade att maskininlärning kan nå tillräcklig prestanda för detektering och skattning av denna avvikelse. Något som också kan användas för återkopplad styrning. Flerdimensionell processdata har samlats i realtid och analyserats med hjälp av bildbehandlingsmetoder.  Dessa data avslöjar brister i nuvarande simuleringsmodeller,vilket i sin tur hjälper till med att bättre förstå och styra lasersvetsning.Resultaten från detta arbete uppvisar en god potential i att använda de föreslagna metoderna för att lösa relevanta utmaningar inom lasersvetsning.

Ort, förlag, år, upplaga, sidor
Trollhättan: University West, 2021. s. 96
Serie
Licentiate Thesis: University West ; 33
Nyckelord
Laser beam welding; Beam shaping, Deformable mirror, Process monitoring, Process control, Model validation, Computer vision, Machine learning, Butt joint, T-joint., Lasersvetsning, Beam shaping, Deformerbar spegel, Processövervakning, Processkontroll, Modellvalidering, Datorsyn, Maskininlärning, Butt joint, T-fogar
Nationell ämneskategori
Bearbetnings-, yt- och fogningsteknik
Identifikatorer
urn:nbn:se:hv:diva-16970 (URN)978-91-88847-96-6 (ISBN)978-91-88847-95-9 (ISBN)
Presentation
2021-08-18, Zoom, University West, Trollhättan, 10:00 (Engelska)
Handledare
Anmärkning

Till licentiatuppsats hör 2 inskickade artiklar, som visas inte nu.

Tillgänglig från: 2021-08-18 Skapad: 2021-08-17 Senast uppdaterad: 2021-11-29
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.
Öppna denna publikation i ny flik eller fönster >>Influence of Laser Beam Shaping on Melt Pool Thermocapillary Flow
2020 (Engelska)Ingår i: 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, artikel-id HTFF 125Konferensbidrag, Publicerat paper (Refereegranskat)
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.

Nyckelord
Thermocapillary Flow, Free surface deformation, Laser beam shaping, Welding, VOF, Open FOAM, Validation
Nationell ämneskategori
Bearbetnings-, yt- och fogningsteknik
Forskningsämne
Produktionsteknik
Identifikatorer
urn:nbn:se:hv:diva-16104 (URN)10.11159/htff20.125 (DOI)
Konferens
6th World Congress on Mechanical, Chemical, and Material Engineering (MCM'20) Prague, Czech Republic Virtual Conference – August, 2020
Anmärkning

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

Tillgänglig från: 2020-12-09 Skapad: 2020-12-09 Senast uppdaterad: 2021-09-01Bibliografiskt granskad
Organisationer
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0002-8018-6145

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