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Frostevarg, Jan, Teknologie doktorORCID iD iconorcid.org/0000-0003-4265-1541
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Publikationer (10 of 82) Visa alla publikationer
Da Silva, A., Frostevarg, J. & Kaplan, A. F. H. (2023). Melt pool monitoring and process optimisation of directed energy deposition via coaxial thermal imaging. Journal of Manufacturing Processes, 107, 126-133
Öppna denna publikation i ny flik eller fönster >>Melt pool monitoring and process optimisation of directed energy deposition via coaxial thermal imaging
2023 (Engelska)Ingår i: Journal of Manufacturing Processes, ISSN 1526-6125, Vol. 107, s. 126-133Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

In Laser-based Directed Energy Deposition of metal powder, the use of optimised parameters allows the deposition of defect-free material, while diverging from these optimised parameters can typically result in high porosity, high dilution or different track geometry. One of the main challenges when building complex geometries is that the geometrical and thermal conditions of the deposition are constantly changing, which requires to adjust the process parameters during the production. In order to facilitate this process, sensors such as thermal cameras can be used to extract data from the process and adapt the parameters to keep the process stable despite external disturbances. In this research, different signals extracted from a coaxial thermal camera are investigated and compared for process optimisation. To investigate such possibilities, five overlapped tracks are deposited at constant laser powers in order to extract average pixel values as well as the melt pool area, length, width and orientation. The behaviour of each track deposition is modelled as a function of the laser power, and these models are used to calculate and test laser power reduction strategies based on different signals. The results show that the melt pool area is the most relevant signal to use for an efficient process control, resulting in a stable process with only ±1.6 % of signal variation from track to track.

Ort, förlag, år, upplaga, sidor
Elsevier, 2023
Nyckelord
Laser cladding, Laser metal deposition, Direct metal deposition, Thermal camera, Process control
Nationell ämneskategori
Bearbetnings-, yt- och fogningsteknik
Forskningsämne
Produktionsutveckling
Identifikatorer
urn:nbn:se:ltu:diva-95797 (URN)10.1016/j.jmapro.2023.10.021 (DOI)001105292800001 ()2-s2.0-85174179072 (Scopus ID)
Projekt
MONACOIDiDI2P
Forskningsfinansiär
Vinnova, 2021-02154Region Norrbotten, 20358021, KO4012
Anmärkning

Validerad;2023;Nivå 2;2023-10-30 (hanlid);

Funder: EU-Interreg Aurora (20358021); EU-Kolarctic CBC (KO4012);

Licens full text: CC BY

Tillgänglig från: 2023-03-06 Skapad: 2023-03-06 Senast uppdaterad: 2024-03-07Bibliografiskt granskad
Da Silva, A., Belelli, F., Lupi, G., Bruzzo, F., Brandau, B., Maier, L., . . . Kaplan, A. (2022). Influence of aluminium powder aging on Directed Energy deposition. Materials & design, 218, Article ID 110677.
Öppna denna publikation i ny flik eller fönster >>Influence of aluminium powder aging on Directed Energy deposition
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2022 (Engelska)Ingår i: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 218, artikel-id 110677Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The use of aluminium alloys for Additive Manufacturing is of high interest for advanced geometries and lightweight applications. In Directed Energy Deposition, a powder stock is processed with a laser beam, which offers a high process flexibility. However, aging of the powder feedstock during storage or after recycling remains fundamentally challenging for aluminium alloys because of their sensitivity to oxida-tion and porosity. In order to investigate these effects, AlSi10Mg powder batches were aged in different conditions and processed by Directed Energy Deposition. The results showed that powder aging does not significantly change the particle size or morphology, but it introduces more oxygen and hydrogen in the powder. The oxidation of the particles reduces the laser beam absorbance of the powder and increases wetting of the melt pool, which affects the track geometry. A 3.5 to 4.2 times higher porosity was observed in the material deposited from aged powder, which are most likely hydrogen pores causedby the increased hydrogen content in the aged powder. The tensile properties of the parts built with aged powder showed 19.0% lower yield strength, 14.2% lower ultimate strength and 99.2% higher elongation, which are most likely the results of the coarser microstructure and increased porosity.

Ort, förlag, år, upplaga, sidor
Elsevier, 2022
Nyckelord
Direct Metal Deposition, Laser Metal Deposition, Laser Powder Bed Fusion, Oxidation, Porosity
Nationell ämneskategori
Bearbetnings-, yt- och fogningsteknik
Forskningsämne
Produktionsutveckling
Identifikatorer
urn:nbn:se:ltu:diva-90849 (URN)10.1016/j.matdes.2022.110677 (DOI)000800225800004 ()2-s2.0-85129120353 (Scopus ID)
Projekt
SAMOA (no. 18079)
Anmärkning

Validerad;2022;Nivå 2;2022-06-02 (sofila);

Funder: EIT Raw Materials.

Tillgänglig från: 2022-06-01 Skapad: 2022-06-01 Senast uppdaterad: 2023-09-04Bibliografiskt granskad
Da Silva, A., Frostevarg, J. & Kaplan, A. F. .. (2022). The influence of laser-induced recoil pressure on particles speed in Directed Energy Deposition. In: M. Schmidt, F. Vollertsen, B.M. Colosimo (Ed.), 12th CIRP Conference on Photonic Technologies [LANE 2022]: . Paper presented at 12th CIRP Conference on Photonic Technologies [LANE 2022], 4-8 September 2022, Fürth, Germany (pp. 381-384). Elsevier, 111
Öppna denna publikation i ny flik eller fönster >>The influence of laser-induced recoil pressure on particles speed in Directed Energy Deposition
2022 (Engelska)Ingår i: 12th CIRP Conference on Photonic Technologies [LANE 2022] / [ed] M. Schmidt, F. Vollertsen, B.M. Colosimo, Elsevier, 2022, Vol. 111, s. 381-384Konferensbidrag, Publicerat paper (Refereegranskat)
Abstract [en]

Directed Energy Deposition is a common Additive Manufacturing technique used for its high deposition rate, but the interactions between the powder stream and the laser beam are still not completely understood. It is known that the powder particles heat up in the laser beam and some theoretical models predict that they can reach vaporization temperature and are significantly accelerated by the recoil pressure. In order to learn more about these phenomena, AlSi10Mg powder streams were observed with a high-speed camera at different laser powers and a particle-tracking software was used to measure the speed of the particles. The results show no significant increase of particle speed near the powder focus where the powder is processed, nor further below the powder focus. The high initial speed of the particles results in a short travelling time through the laser beam and in a very small effect of the recoil pressure.

Ort, förlag, år, upplaga, sidor
Elsevier, 2022
Serie
Procedia CIRP, ISSN 2212-8271
Nyckelord
Direct Metal Deposition, Laser Metal Deposition, recoil pressure
Nationell ämneskategori
Atom- och molekylfysik och optik Annan fysik Strömningsmekanik och akustik
Forskningsämne
Produktionsutveckling
Identifikatorer
urn:nbn:se:ltu:diva-92864 (URN)10.1016/j.procir.2022.08.171 (DOI)2-s2.0-85141899832 (Scopus ID)
Konferens
12th CIRP Conference on Photonic Technologies [LANE 2022], 4-8 September 2022, Fürth, Germany
Anmärkning

Funder: EIT Raw Materials, project SAMOA (no. 18079)

Tillgänglig från: 2022-09-08 Skapad: 2022-09-08 Senast uppdaterad: 2022-12-06Bibliografiskt granskad
Da Silva, A., Frostevarg, J. & Kaplan, A. F. .. (2022). Thermal monitoring for directed energy deposition of stainless steel, bronze, and cobalt-based alloy. Surface & Coatings Technology, 451, Article ID 129078.
Öppna denna publikation i ny flik eller fönster >>Thermal monitoring for directed energy deposition of stainless steel, bronze, and cobalt-based alloy
2022 (Engelska)Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 451, artikel-id 129078Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Laser cladding and Directed Energy Deposition are two related processes that allow the deposition of specific surface coatings and the production of additively manufactured parts. In both processes, the selection of optimised parameters results in the deposition of high-density material with low dilution. However, the thermal and geometrical conditions constantly change during the process and the parameters need to be continually adapted in order to avoid defects or poor properties. In this context, the development of closed-loop monitoring systems is crucial in order to widen the field of possible applications towards more complexity, with a more stable process and higher materials properties. In this research, the possibility of thermal monitoring with middle-wave and long-wave infra-red cameras is investigated for Directed Energy Deposition of 316L, Stellite 21 and CuSn10. The melt pool length and the cooling rate are extracted from thermal imaging while the laser power was varied, and these results are compared to the materials properties of the deposited tracks. The main results show that an increase of melt pool length results in a decrease of porosity and an increase of dilution, which induces a change of hardness. The melt pool length can be regulated by adjusting the laser power in order to keep both the porosity and the dilution within acceptable values.

Ort, förlag, år, upplaga, sidor
Elsevier, 2022
Nyckelord
Copper, Dilution, Laser cladding, Laser metal deposition, Porosity
Nationell ämneskategori
Bearbetnings-, yt- och fogningsteknik
Forskningsämne
Produktionsutveckling
Identifikatorer
urn:nbn:se:ltu:diva-94289 (URN)10.1016/j.surfcoat.2022.129078 (DOI)000891100700002 ()2-s2.0-85142195979 (Scopus ID)
Projekt
MONACO
Forskningsfinansiär
Vinnova, 2021-02154 MONACO
Anmärkning

Validerad;2022;Nivå 2;2022-11-28 (hanlid)

Tillgänglig från: 2022-11-28 Skapad: 2022-11-28 Senast uppdaterad: 2023-05-08Bibliografiskt granskad
Da Silva, A., Volpp, J., Frostevarg, J. & Kaplan, A. F. . (2021). Acceleration of metal drops in a laser beam. Applied Physics A: Materials Science & Processing, 127(1), Article ID 4.
Öppna denna publikation i ny flik eller fönster >>Acceleration of metal drops in a laser beam
2021 (Engelska)Ingår i: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 127, nr 1, artikel-id 4Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Different processes require the detachment of metal drops from a solid material using a laser beam as the heat source, for instance laser drop generation or cyclam. These techniques imply that the drops enter the laser beam, which might affect their trajectory. Also, many laser processes such as laser welding or additive manufacturing generate spatters that can be accelerated by the laser beam during flight and create defects on the material. This fundamental study aims at investigating the effects of a continuous power laser beam on the acceleration of intentionally detached drops and unintentionally detached spatters. Two materials were studied: 316L steel and AlSi5 aluminium alloy. High-speed imaging was used to measure the position of the drops and calculate their acceleration to compare it to theoretical models. Accelerations up to 11.2 g could be measured. The contributions of the vapor pressure, the recoil pressure, and the radiation pressure were investigated. The recoil pressure was found to be the main driving effect but other phenomena counteract this acceleration and reduce it by an order of magnitude of one to two. In addition, two different vaporization regimes were observed, resulting respectively in a vapor plume and in a vapor halo around the drop.

Ort, förlag, år, upplaga, sidor
Springer, 2021
Nyckelord
Laser ablation propulsion, Laser drop generation, Recoil pressure, Ablation pressure, Spatters trajectory
Nationell ämneskategori
Bearbetnings-, yt- och fogningsteknik
Forskningsämne
Produktionsutveckling
Identifikatorer
urn:nbn:se:ltu:diva-82252 (URN)10.1007/s00339-020-04177-y (DOI)000599501100001 ()2-s2.0-85097611880 (Scopus ID)
Projekt
LAM-4DSYMAXSAMOAC3TS
Forskningsfinansiär
Vinnova, 2018-04324Interreg Nord, 20201279
Anmärkning

Validerad;2021;Nivå 2;2021-01-11 (johcin);

Finansiär: SYMAX (2019-02458) EIT Raw Materials, project SAMOA (18079);

For correction, see: Da Silva, A., Volpp, J., Frostevarg, J. et al. Correction: Acceleration of metal drops in a laser beam. Appl. Phys. A 129, 637 (2023). https://doi.org/10.1007/s00339-023-06853-1

Tillgänglig från: 2021-01-11 Skapad: 2021-01-11 Senast uppdaterad: 2023-09-04Bibliografiskt granskad
Da Silva, A., Frostevarg, J., Volpp, J. & Kaplan, A. (2021). Additive Manufacturing by laser-assisted drop deposition from a metal wire. Materials & design, 209, Article ID 109987.
Öppna denna publikation i ny flik eller fönster >>Additive Manufacturing by laser-assisted drop deposition from a metal wire
2021 (Engelska)Ingår i: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 209, artikel-id 109987Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The subject of Additive Manufacturing includes numerous techniques, some of which have reached very high levels of development and are now used industrially. Other techniques such as Micro Droplet Deposition Manufacture are under development and present different manufacturing possibilities, but are employed only for low melting temperature metals. In this paper, the possibility of using a laser-based drop deposition technique for stainless-steel wire is investigated. This technique is expected to be a more flexible alternative to Laser Metal Wire Deposition. Laser Droplet Generation experiments were carried out in an attempt to accurately detach steel drops towards a desired position. High-speed imaging was used to observe drop generation and measure the direction of detachment of the drops. Two drop detachment techniques were investigated and the physical phenomena leading to the drop detachment are explained, wherein the drop weight, the surface tension and the recoil pressure play a major role. Optimised parameters for accurate single drop detachment were identified and then used to build multi-drop tracks. Tracks with an even geometry were produced, where the microstructure was influenced by the numerous drop depositions. The tracks showed a considerably higher hardness than the base wire, exhibiting a relatively homogeneous macro-hardness with a localised softening effect at the interfaces between drops.

Ort, förlag, år, upplaga, sidor
Elsevier, 2021
Nyckelord
Laser Metal Wire Deposition, Wire-Laser Additive Manufacturing, Laser Droplet Generation, Laser Droplet Formation Process, Drop-on-Demand
Nationell ämneskategori
Bearbetnings-, yt- och fogningsteknik
Forskningsämne
Produktionsutveckling
Identifikatorer
urn:nbn:se:ltu:diva-83628 (URN)10.1016/j.matdes.2021.109987 (DOI)000701685800004 ()2-s2.0-85110453172 (Scopus ID)
Projekt
LAM-4DLAM-4D stage 2SAMOA
Forskningsfinansiär
Vinnova, 2018-04324; 2019-04872
Anmärkning

Validerad;2021;Nivå 2;2021-07-26 (beamah);

Ytterligare forskningsfinansiär: EIT Raw Materials (no. 18079)

Tillgänglig från: 2021-04-13 Skapad: 2021-04-13 Senast uppdaterad: 2023-03-07Bibliografiskt granskad
Volpp, J. & Frostevarg, J. (2021). Elongated cavities during keyhole laser welding. Materials & design, 206, 109835, Article ID 109835.
Öppna denna publikation i ny flik eller fönster >>Elongated cavities during keyhole laser welding
2021 (Engelska)Ingår i: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 206, s. 109835-, artikel-id 109835Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

During laser beam deep penetration welding, the characteristic keyhole occurs that enables efficient energy absorption due to multiple reflections. Since this welding mode usually shows high dynamic behaviour, often a high amount of weld imperfections like spattering or porosity occur. Elongated keyholes during buttonhole, a.k.a donut welding, have shown the possibility to create smooth welding tracks when controlled variations of energy input were induced, e.g. beam oscillation. It was observed that the elongated keyholes can maintain themselves due to the balancing effects of the melt pool surface tension, which can form a catenoid shape that does not require any additional forces to be stable. Basic theoretical descriptions of the catenoid shape keyholes were derived. However, the complex system requires a more detailed investigation of the effect of the metal plume and the melt flows in order to explain the opening and maintenance effects of the elongated keyholes.

Therefore, this work examined different modes of elongated keyholes, comparing traditional non-oscillating keyholes to keyholes formed by different beam scanning strategies. Analysis was made mainly by observations with high-speed-imaging and theoretical considerations to explain the phenomena of elongated keyholes. The observations showed that extended keyholes are not necessarily related to a reduced occurrence of imperfections and not either to the formation of perfect catenoid shapes. The keyhole front is deformed where the laser beam impacts and the rear wall is impacted where the vapour plume strikes. The opening of an elongated keyhole is likely related to the keyhole vapour plume that pushes the keyhole rear wall rearwards, while the non-affected rear wall parts do not collapse the keyhole due to the balancing nature of the second curvature of the rear wall.

Ort, förlag, år, upplaga, sidor
Elsevier, 2021
Nyckelord
Donut welding, buttonhole welding, metal vapour pressure, beam oscillation, high speed imaging
Nationell ämneskategori
Bearbetnings-, yt- och fogningsteknik
Forskningsämne
Produktionsutveckling
Identifikatorer
urn:nbn:se:ltu:diva-84297 (URN)10.1016/j.matdes.2021.109835 (DOI)000661918000003 ()2-s2.0-85106340539 (Scopus ID)
Forskningsfinansiär
Vetenskapsrådet, 2020-04250
Anmärkning

Validerad;2021;Nivå 2;2021-06-07 (johcin);

Forskningafinansiärer: Permanova AB; SteelS4EV – STEEL Solutions for Safe and Smart Structures of Electric Vehicles (EC Research Fund for Coal and Steel, RFCS, no. 800726); ACCEL – Adapted Chemical Composition of materials for Enhanced Laser welding (Vinnova SIP Production 2030 project 2019-0078); SAMOA - Sustainable Aluminium additive Manufacturing for high performance Applications (EIT raw materials, no. 18079); SPAcEMAN - Sustainable Powders for AdditivE MANufacturing (EIT raw materials, no. 17070)

Tillgänglig från: 2021-05-17 Skapad: 2021-05-17 Senast uppdaterad: 2021-06-28Bibliografiskt granskad
Robertson, S., Frostevarg, J., Näsström, J., Berndtsson, T. & Kaplan, A. (2021). Evaluation of pre-determined dilution of high strength steels by the Snapshot method. Optics and lasers in engineering, 139, Article ID 106512.
Öppna denna publikation i ny flik eller fönster >>Evaluation of pre-determined dilution of high strength steels by the Snapshot method
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2021 (Engelska)Ingår i: Optics and lasers in engineering, ISSN 0143-8166, E-ISSN 1873-0302, Vol. 139, artikel-id 106512Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Dilution is an unavoidable consequence of multi-material fusion processing, i.e. welding, cladding etc. In this paper we propose a novel method for controlled dilution experiments, analyzing microstructural trends of steel filler wire diluted with steel base metal. The highlight of this method is the control of processing conditions used to melt a pre-determined dilution of two high strength steels. The materials involved are S960QL base metal machining chips and a chopped under-matched wire consumable, which is used to increase the toughness of welded joints. These materials were combined in specific mass ratios in a prepared cavity and then melted by a pulsed laser beam. A high-speed RGB camera evaluated the relative spatial temperature of the melt surface. The molten mass then solidified into a uniform nugget, confirmed by energy dispersive x-ray spectrometry (EDS) to have a homogenous chemical composition (a ‘Snapshot’ nugget). Hardness values obtained for different dilution levels were compared to a narrow gap multi-layer laser weld (NGMLW), with a decreased dilution rate yielding a decreased hardness. The Snapshot microstructures created are similar to the different regions of the NGMLW, in the weld cap and in the body of the weld. Snapshot nuggets were also evaluated for non-metallic inclusion (NMI) size distributions relating to the dilution levels (NMIs are important indicators for acicular ferrite, which has been shown to increase impact toughness).

Ort, förlag, år, upplaga, sidor
Elsevier, 2021
Nyckelord
Dilution, Narrow gap multi-layer welding, Laser welding, Snapshot method, Energy dispersive x-ray spectroscopy
Nationell ämneskategori
Bearbetnings-, yt- och fogningsteknik
Forskningsämne
Produktionsutveckling
Identifikatorer
urn:nbn:se:ltu:diva-82060 (URN)10.1016/j.optlaseng.2020.106512 (DOI)000614093000044 ()2-s2.0-85097904003 (Scopus ID)
Forskningsfinansiär
Interreg Nord, 2014-2020Europeiska regionala utvecklingsfonden (ERUF), 304-15588-2015Vinnova, 2019-00781
Anmärkning

Validerad;2021;Nivå 2;2021-01-01 (johcin);

Finansiär: EC Research Fund for Coal and Steel (709954)

Tillgänglig från: 2020-12-18 Skapad: 2020-12-18 Senast uppdaterad: 2021-05-07Bibliografiskt granskad
Dewi, H. S., Volpp, J., Frostevarg, J. & Siltanen, J. (2021). Influence of mill scale on oxygen laser cutting processes. In: IOP Conference Series: Materials Science and Engineering: . Paper presented at 18th Nordic Laser Materials Processing Conference (18th NOLAMP), Luleå, Sweden, January 18-20, 2022. Institute of Physics (IOP), 1135, Article ID 012008.
Öppna denna publikation i ny flik eller fönster >>Influence of mill scale on oxygen laser cutting processes
2021 (Engelska)Ingår i: IOP Conference Series: Materials Science and Engineering, Institute of Physics (IOP), 2021, Vol. 1135, artikel-id 012008Konferensbidrag, Publicerat paper (Refereegranskat)
Abstract [en]

Mill scale formed on the surface of hot rolled steels consists of magnetite (Fe3O4), hematite (Fe2O3) and wustite (FeO) layers, which can protect the steels from corrosion and other atmospheric effects. Existence of mill scale on the specimens' surface has shown to be able to decrease the cut edge quality. Since the mechanism behind influence of mill scale on the laser cutting process is unknown, this work performs direct observation of oxygen laser cutting processes on specimens with and without removed mill scale layers. Oxygen laser cutting processes were carried out using Ytterbium fibre laser 1070 nm along the edge of 20-mm-thick-steel specimens which were attached to a borosilicate glass. Focal point of the laser beam was positioned to be 0.7 mm below the specimens' surface. A high speed imaging system was arranged to face the glass, recording the cut front and kerf dynamics during cutting processes. It was found that cut front inclination angle increase when the mill scale was removed from the specimens' surface. This implies that mill scale on the specimens' surface seem to contribute in increasing the exothermal energy during laser cutting processes.

Ort, förlag, år, upplaga, sidor
Institute of Physics (IOP), 2021
Serie
IOP Conference Series: Materials Science and Engineering, ISSN 1757-8981, E-ISSN 1757-899X
Nationell ämneskategori
Bearbetnings-, yt- och fogningsteknik
Forskningsämne
Produktionsutveckling
Identifikatorer
urn:nbn:se:ltu:diva-90022 (URN)10.1088/1757-899X/1135/1/012008 (DOI)000766307500008 ()
Konferens
18th Nordic Laser Materials Processing Conference (18th NOLAMP), Luleå, Sweden, January 18-20, 2022
Forskningsfinansiär
Vinnova, 2019-00781_VINNOVA
Tillgänglig från: 2022-03-31 Skapad: 2022-03-31 Senast uppdaterad: 2022-04-11Bibliografiskt granskad
Anthony, N., Frostevarg, J., Suhonen, H. & Granvik, M. (2021). Laboratory experiments with a laser-based attachment mechanism for spacecraft at small bodies. Acta Astronautica, 189, 391-397
Öppna denna publikation i ny flik eller fönster >>Laboratory experiments with a laser-based attachment mechanism for spacecraft at small bodies
2021 (Engelska)Ingår i: Acta Astronautica, ISSN 0094-5765, E-ISSN 1879-2030, Vol. 189, s. 391-397Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

We present the results of two sets of experiments that investigate laser-based metal-to-rock attachment techniques. Asteroids and comets have low surface gravity which pose a challenge to landers with moving parts. Such parts can generate torques and forces which may tip the lander over or launch it into deep space. Thus, if a lander on a small body is to have moving parts, the spacecraft must be equipped with an anchoring mechanism. To this end, we sought to use a laser to melt and bind a piece of metal mimicking a part of a spacecraft to a rock mimicking the surface of a typical asteroid. In the first set of experiments, extra material was not fed in during the processing. The second set were performed using a standard wire feeder used in laser welding, which added metal to the experiment during processing. During the first experiments, we discovered that a traditional weld, where two melt pools mix and solidify to form a strong bond, was not possible—the melt pools would not mix, and when they did, the resulting weld was extremely brittle. The second set of experiments resulted in a physico-mechanical bond, where a hole was drilled with a laser, and a wire was melted and fed into the hole. These latter experiments were successful in forming bonds as strong as 115 N. Such an attachment mechanism can also be used to maneuver small boulders on asteroid surfaces, to redirect small, monolithic asteroids, or in space-debris removal.

Ort, förlag, år, upplaga, sidor
Elsevier, 2021
Nyckelord
Spacecraft anchoring, Laser drilling, High-speed imaging, X-ray micro-tomography, Asteroid mining
Nationell ämneskategori
Annan elektroteknik och elektronik Astronomi, astrofysik och kosmologi
Forskningsämne
Produktionsutveckling; Rymdtekniska system
Identifikatorer
urn:nbn:se:ltu:diva-86924 (URN)10.1016/j.actaastro.2021.08.028 (DOI)000703817900035 ()2-s2.0-85114802051 (Scopus ID)
Forskningsfinansiär
Knut och Alice Wallenbergs Stiftelse
Anmärkning

Validerad;2021;Nivå 2;2021-09-14 (beamah)

Tillgänglig från: 2021-08-31 Skapad: 2021-08-31 Senast uppdaterad: 2021-12-13Bibliografiskt granskad
Organisationer
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0003-4265-1541

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