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Koti, D., Powell, J., Naesstroem, H., Spaccapaniccia, C. & Voisey, K. T. (2023). Laser cladding: A high-speed-imaging examination of powder catchment efficiency as a function of the melt pool geometry and its position under the powder stream. Journal of laser applications, 35(4), Article ID 042065.
Open this publication in new window or tab >>Laser cladding: A high-speed-imaging examination of powder catchment efficiency as a function of the melt pool geometry and its position under the powder stream
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2023 (English)In: Journal of laser applications, ISSN 1042-346X, E-ISSN 1938-1387, Vol. 35, no 4, article id 042065Article in journal (Refereed) Published
Abstract [en]

This paper provides quantitative information about the paths taken by blown powder particles during laser cladding. A proportion of the powder is "wasted" by bouncing off the solid areas surrounding the melt pool. This wastage reduces the productivity and profitability of the process. In this paper, specially developed software was used to analyze high-speed imaging videos of the cladding process, to monitor the directions of powder particle flight toward and away from the melt pool area. This information has been correlated to the geometry and position of the melt pool zone for three different cladding techniques: single track cladding (A tracks), standard overlapping track cladding (AAA cladding), and a recently developed technique called ABA cladding. The results show that the melt pool geometry, and particularly the overlap between the melt pool and the incoming powder stream, has a strong influence on powder catchment efficiency. ABA cladding was found to have considerably better powder catchment efficiency than standard AAA cladding and this improvement can be explained by consideration of the geometries and positions of the melt pools and surrounding solid material in each case. As powder costs are an important factor in industrial laser cladding, the adaption of the ABA technique, and/or control of pool/powder stream overlap (e.g., by making the powder stream not coaxial with the laser beam), could improve the profitability of the process.

Place, publisher, year, edition, pages
Laser Institute of America (LIA), 2023
Keywords
ABA laser cladding, DED, High-speed imaging, Laser cladding, Laser direct energy deposition, Powder catchment efficiency, Powder stream, Productivity
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-102646 (URN)10.2351/7.0001199 (DOI)2-s2.0-85176366063 (Scopus ID)
Note

Validerad;2023;Nivå 2;2023-11-23 (hanlid);

Full text license: CC BY

Available from: 2023-11-23 Created: 2023-11-23 Last updated: 2023-11-23Bibliographically approved
Koti, D., Powell, J., Naesstroem, H. & Voisey, K. T. (2023). Powder catchment efficiency in laser cladding (directed energy deposition). An investigation into standard laser cladding and the ABA cladding technique. Journal of laser applications, 35(1), Article ID 012025.
Open this publication in new window or tab >>Powder catchment efficiency in laser cladding (directed energy deposition). An investigation into standard laser cladding and the ABA cladding technique
2023 (English)In: Journal of laser applications, ISSN 1042-346X, E-ISSN 1938-1387, Vol. 35, no 1, article id 012025Article in journal (Refereed) Published
Abstract [en]

This paper investigates the efficiency of powder catchment in blown powder laser cladding (a directed energy deposition technique). A comparison is made between standard "track by overlapping track"cladding ("AAA"cladding) and "ABA"cladding, where the gaps left between an initial set of widely spaced tracks ("A"tracks), are filled in by subsequent "B"tracks. In both these techniques, the melt pool surface is the collection area for the cladding powder, and the shape of this pool can be affected by several parameters including cladding speed, intertrack spacing, and type of cladding technique. The results presented here are derived from of an analysis of high-speed videos taken during processing and cross sections of the resultant clad tracks. The results show that the first track in AAA cladding has a different melt pool shape to subsequent tracks, and that the asymmetry of the subsequent track melt pools results in a reduction in the powder catchment efficiency. In contrast to this, the geometry of the "B"track melt pools between their adjacent "A"tracks results in an enhanced powder catchment efficiency.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2023
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-95805 (URN)10.2351/7.0000904 (DOI)2-s2.0-85148668500 (Scopus ID)
Note

Validerad;2023;Nivå 2;2023-03-07 (joosat);

Licens fulltext: CC BY License

Available from: 2023-03-07 Created: 2023-03-07 Last updated: 2023-03-07Bibliographically approved
Naesstroem, H., Brückner, F. & Kaplan, A. F. H. (2022). Blown powder directed energy deposition on various substrate conditions. Journal of Manufacturing Processes, 73, 660-667
Open this publication in new window or tab >>Blown powder directed energy deposition on various substrate conditions
2022 (English)In: Journal of Manufacturing Processes, ISSN 1526-6125, Vol. 73, p. 660-667Article in journal (Refereed) Published
Abstract [en]

Blown powder directed energy deposition of SS316L powder is carried out on various substrate surface conditions of SS304 such as cleaned, sand blasted, milled, oily, cold galvanised and painted to study their influence on the process. High-speed imaging is used for process observation and the deposited tracks are analysed qualitatively and quantitatively using surface images, cross sectional macrographs and x-ray images. Frames from high-speed imaging reveal the removal of additional material from the substrate surface such as paint and oil. The stages involved in their removal: peeling and evaporation are presented. EDS analysis showed that no additional elements other than powder and substrate material are found in the track volume. The quantitative results for all specimens show that the surface conditions had minor influences on track width, track height, wetting angle, dilution and deposited cross sectional area. Defects such as porosity, inclusions and cracking were not observed related to the surface conditions. These findings could significantly reduce processing time by skipping the cleaning step before directed energy deposition such as laser cladding or repair in industrial applications.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Laser cladding, Laser metal deposition, Surface conditions, Contaminated surfaces, High-speed imaging
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-83612 (URN)10.1016/j.jmapro.2021.11.048 (DOI)000740842200001 ()2-s2.0-85120158320 (Scopus ID)
Note

Validerad;2021;Nivå 2;2021-12-02 (johcin)

Available from: 2021-04-13 Created: 2021-04-13 Last updated: 2023-09-13Bibliographically approved
Naesstroem, H., Brueckner, F. & Kaplan, A. F. .. (2021). From mine to part: Directed energy deposition of iron ore. Rapid prototyping journal, 27(11), 37-42
Open this publication in new window or tab >>From mine to part: Directed energy deposition of iron ore
2021 (English)In: Rapid prototyping journal, ISSN 1355-2546, E-ISSN 1758-7670, Vol. 27, no 11, p. 37-42Article in journal (Refereed) Published
Abstract [en]

Purpose - This paper aims to gain an understanding of the behaviour of iron ore when melted by a laser beam in a continuous manner. This fundamental knowledge is essential to further develop additive manufacturing routes such as production of low cost parts and in-situ reduction of the ore during processing.

Design/methodology/approach - Blown powder directed energy deposition was used as the processing method. The process was observed through high-speed imaging, and computed tomography was used to analyse the specimens.

Findings - The experimental trials give preliminary results showing potential for the processability of iron ore for additive manufacturing. A large and stable melt pool is formed in spite of the inhomogeneous material used. Single and multilayer tracks could be deposited. Although smooth and even on the surface, the single layer tracks displayed porosity. In case of multilayered tracks, delamination from the substrate material and deformation can be seen. High-speed videos of the process reveal various process phenomena such as melting of ore powder during feeding, cloud formation, melt pool size, melt flow and spatter formation.

Originality/value - Very little literature is available that studies the possible use of ore in additive manufacturing. Although the process studied here is not industrially useable as is, it is a step towards processing cheap unprocessed material with a laser beam.

Place, publisher, year, edition, pages
Emerald Group Publishing Limited, 2021
Keywords
Additive manufacturing, Additive manufacturing, Laser cladding, Crushed iron ore, High-speed imaging, Laser metal deposition
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-83611 (URN)10.1108/RPJ-10-2020-0243 (DOI)000691456900001 ()2-s2.0-85113835505 (Scopus ID)
Funder
Interreg Nord, 304-10694-2017, 304-7463-2018
Note

Validerad;2021;Nivå 2;2021-09-08 (alebob);

Har tidigare förekommit som manuskript i avhandling.

Available from: 2021-04-13 Created: 2021-04-13 Last updated: 2021-09-08Bibliographically approved
Naesstroem, H. (2021). Phenomena in laser based material deposition. (Doctoral dissertation). Luleå University of Technology
Open this publication in new window or tab >>Phenomena in laser based material deposition
2021 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Fenomen i laserbaserad materialdeponering
Abstract [en]

This thesis is regarding the use of a laser beam to deposit material. Phenomena in two processes, laser beam welding with filler wire and blown powder directed energy deposition (DED) also known as laser metal deposition (LMD)1, are discussed. High-speed imaging is used as a central tool, supported by cross-sectional macrographs, surface images, X-ray images, computed tomography scans and quantitative analysis of the acquired results to observe many phenomena. Several results generated could be used in the manufacturing industry.

A novel concept of feeding the filler wire off-axis to the joint in laser beam welding is presented. The formation of defects called undercuts depended mainly on the stability of the wire feed and irregular melting of its tip. Process parameters played a key role in the robustness of the process, with higher welding speeds and laser powers increasing the chance for formation of defects.

Powder catchment in DED, and the various influencing factors are discussed. The position of initial interaction between powder grains and the melt pool plays an important role in defining incorporation behaviour. Powder grains can float on the surface of melt pool and travel along the direction of surface tension driven melt flows before fully incorporating. In high-deposition rate DED, an island of unmelted powder can form in the melt pool, depending on the laser beam shape and powder feeding configuration used. This island could lead to formation of spatter from the melt pool and porosity in resulting clads. Solid oxide skins present on the melt pool in low temperature areas can act like a barrier preventing complete incorporation of powder grains or possibly causing localised boiling, forming spatter.

For the first time, near-unprocessed material was used as feedstock in the DED process. A single large melt pool is formed in the relatively calm process, and phenomena like cloud formation while feeding of material and spatter were observed. Single and multi-layered deposition resulted in porous tracks and delamination from the substrate. While the process is not industrially useable in its current state, it is a step towards processing cheap unprocessed material with a laser beam to manufacture low cost parts or for in-situ reduction. 

The roles of material composition and surface conditions of the substrate in DED are also presented. Both, the composition and surface condition affect the absorption of the laser radiation. Material composition influences the time taken for incorporation of powder grains. The size of the melt pool and dilution depends on the thermal conductivity of the substrate material. Surfaces that are rough or coated with (several sorts of) paint produce wider tracks, with better wetting angles as compared to milled or ground surfaces. Coatings like paints or cold-galvanising primers do not negatively affect the process. Deposition directly on rough or painted surfaces could significantly reduce processing time and the resources needed for cleaning before cladding or repair processes. 

Place, publisher, year, edition, pages
Luleå University of Technology, 2021
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-83613 (URN)978-91-7790-819-7 (ISBN)978-91-7790-820-3 (ISBN)
Public defence
2021-06-10, A109, Luleå tekniska universitet, Luleå, 09:00 (English)
Opponent
Supervisors
Available from: 2021-04-14 Created: 2021-04-13 Last updated: 2021-11-12Bibliographically approved
Prasad, H. S., Brueckner, F., Volpp, J. & Kaplan, A. F. H. (2020). Laser metal deposition of copper on diverse metals using green laser sources. The International Journal of Advanced Manufacturing Technology, 107(3-4), 1559-1568
Open this publication in new window or tab >>Laser metal deposition of copper on diverse metals using green laser sources
2020 (English)In: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 107, no 3-4, p. 1559-1568Article in journal (Refereed) Published
Abstract [en]

Green laser sources are advantageous in the processing of copper due to the increase of absorptivity compared with more commonly available infrared lasers. Laser metal deposition of copper with a green laser onto various substrate metals namely copper, aluminium, steel and titanium alloy was carried out and observed through high-speed imaging. The effects of process parameters such as laser power, cladding speed and powder feed rate, and material attributes such as absorptivity, surface conditions and thermal conductivity are tied together to explain the size and geometry of the melt pool as well as the fraction of the power used for melting material. The copper substrate has the smallest melt pool with a high angle, followed by aluminium, steel and titanium alloy. The incorporation times for powder grains in the melt pools vary based on the substrate materials. Its dependency on material properties, including surface tension forces, melting temperatures and material density, is discussed. Oxide skins present on melt pools can affect powder incorporation, most significantly on the aluminium substrate. The lower limits of the fraction of power irradiated on the surface used purely for melting were calculated to be 0.73%, 2.94%, 5.95% and 9.78% for the copper, aluminium, steel and titanium alloy substrates, respectively, showing a strong dependence on thermal conductivity of the substrate material. For a copper wall built, the fraction was 2.66%, much higher than a single clad on a copper substrate, due to reduced workpiece heating. The results of this paper can be transferred to other metals with low absorptivity such as gold.

Place, publisher, year, edition, pages
Springer, 2020
Keywords
Copper, Laser Metal Deposition, Additive Manufacturing, High Speed Imaging, Multi-material, Green 515 nm laser, Directed Energy Deposition, Absorptivity, Powder grain incorporation, LMD, DED
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-73753 (URN)10.1007/s00170-020-05117-z (DOI)000521121600003 ()2-s2.0-85081542493 (Scopus ID)
Note

Validerad;2020;Nivå 2;2020-04-23 (johcin)

Available from: 2019-04-24 Created: 2019-04-24 Last updated: 2021-04-13Bibliographically approved
Prasad, H. S., Brueckner, F. & Kaplan, A. F. .. (2020). Powder incorporation and spatter formation in high deposition rate blown powder directed energy deposition. Additive Manufacturing, 35, Article ID 101413.
Open this publication in new window or tab >>Powder incorporation and spatter formation in high deposition rate blown powder directed energy deposition
2020 (English)In: Additive Manufacturing, E-ISSN 2214-8604, Vol. 35, article id 101413Article in journal (Refereed) Published
Abstract [en]

A high deposition rate blown powder directed energy deposition process is presented. Clad tracks are deposited and the process is observed by high-speed imaging. An island of unmelted powder forms inside the melt pool, in the centre of the laser spot, which can be attributed to the highly focussed powder flow and the laser beam configuration used. On contact with the melt pool, the powder grains melt to join the melt pool, or they overcome surface tension and are engulfed by the melt. Powder grains can also incorporate into a mushy zone that may be present on the powder island. The powder island appears to rotate in the melt pool and incorporates relatively slowly. The speed of rotation is connected to the size of the island, which also depends on the energy density used. Spatter can form from the edges of the melt pool or from areas around the island when molten metal droplets burst. Frames from high-speed videos are presented and reasons for the various phenomena observed are discussed.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Laser cladding, Island formation, Laser Metal Deposition, Powder catchment, Spatter, High-speed imaging
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-80090 (URN)10.1016/j.addma.2020.101413 (DOI)000576651400005 ()2-s2.0-85086827120 (Scopus ID)
Note

Validerad;2020;Nivå 2;2020-06-29 (alebob)

Available from: 2020-06-29 Created: 2020-06-29 Last updated: 2021-04-13Bibliographically approved
Volpp, J. & Prasad, H. S. (2019). Impact of powder application on particle incorporation during direct metal deposition. In: Proceedings of LAMP2019: The 8th International Congress on Laser Advanced Materials Processing. Paper presented at The 8th International Congress on Laser Advanced Materials Processing (LAMP2019), 21-24 May, 2019, Hiroshima, Japan. Japan, Article ID 19-045.
Open this publication in new window or tab >>Impact of powder application on particle incorporation during direct metal deposition
2019 (English)In: Proceedings of LAMP2019: The 8th International Congress on Laser Advanced Materials Processing, Japan, 2019, article id 19-045Conference paper, Published paper (Refereed)
Abstract [en]

Direct Metal Deposition as a method of Additive Manufacturing is widely used in many industrial fields and promises wider use due to its potential of building fine tracks as well as structures with high build-up rates. In order to guarantee a high powder-usage efficiency and a minimum contamination of the environment, the incorporation process of the powder into the melt pool needs to be better understood. Therefore, single additive tracks were built at varying powder application direction and gas flow rates. An evaluation of the track dimensions revealed that powder application properties affect the track dimensions and the powder input efficiency. The gas pressure and the application angle can influence the melt pool shape and thereby the powder input efficiency. A higher gas pressure possibly deforms the melt pool to a steeper surface, resulting in a higher probability of powder particle incorporation.

Place, publisher, year, edition, pages
Japan: , 2019
Keywords
Additive Manufacturing, powder particle incorporation, Gas pressure, Powder nozzle angle
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-78435 (URN)
Conference
The 8th International Congress on Laser Advanced Materials Processing (LAMP2019), 21-24 May, 2019, Hiroshima, Japan
Available from: 2020-04-09 Created: 2020-04-09 Last updated: 2023-09-04Bibliographically approved
Frostevarg, J., Volpp, J., Thompson, C., Prasad, H. S., Fedina, T. & Brückner, F. (2019). Influence of the vapour channel on processing in laser powder bed fusion. Paper presented at 17th Nordic Laser Materials Processing Conference (NOLAMP17), 27-29 August, 2019, Trondheim, Norway. Procedia Manufacturing, 36, 80-87
Open this publication in new window or tab >>Influence of the vapour channel on processing in laser powder bed fusion
Show others...
2019 (English)In: Procedia Manufacturing, E-ISSN 2351-9789, Vol. 36, p. 80-87Article in journal (Refereed) Published
Abstract [en]

Additive Manufacturing provides many opportunities to design and manufacture parts that are difficult or not possible to produce with conventional methods. In Selective Laser Melting (SLM) in powder bed fusion (PBF), melt pool dynamics and stability is dependent on a large number of factors, e.g. laser power output, power density, travel speed, reflectivity of powder bed, rapid heating and vaporization. Since travel speeds are often very fast and the laser interaction zone is small, the physical events become difficult to predict but also to observe. This work aims to describe the formation and geometrical characteristics of the vaporization zone during processing. Using a combination of theoretical descriptions, resulting material structures and a comprehensive analysis of high-speed images of the processing zone for different heat inputs and travel speeds, explanations for the dynamic melt pool behaviour are derived. The melting and pressures from processing involved moves powder particles next to it, changing the conditions for neighbouring tracks due to lack of material. These findings can provide a basis for creating more efficient and stable SLM processing, with fewer imperfections.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
High speed imaging, SLMPowder movement, Pressure
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-75755 (URN)10.1016/j.promfg.2019.08.012 (DOI)000610364700011 ()2-s2.0-85072535737 (Scopus ID)
Conference
17th Nordic Laser Materials Processing Conference (NOLAMP17), 27-29 August, 2019, Trondheim, Norway
Note

Konferensartikel i tidskrift

Available from: 2019-08-29 Created: 2019-08-29 Last updated: 2023-09-06Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-7213-0002

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