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Näsström, J., Brueckner, F. & Kaplan, A. (2020). A near-vertical approach to Laser Narrow Gap Multi-Layer Welding. Optics and Laser Technology, 121, Article ID 105798.
Open this publication in new window or tab >>A near-vertical approach to Laser Narrow Gap Multi-Layer Welding
2020 (English)In: Optics and Laser Technology, ISSN 0030-3992, E-ISSN 1879-2545, Vol. 121, article id 105798Article in journal (Refereed) Published
Abstract [en]

A novel, near-vertical approach to the usually horizontal laser Narrow Gap Multi-Layer Welding process is introduced. The process is applied to join X100 pipeline steel and studied through High Speed Imaging. The produced welded joints are compared to their horizontally welded counterparts using 3D scanning, longitudinal & perpendicular cross sections and Computed Tomography analysis. The near-vertical approach is found to be robust and produce welded joints with a uniform appearance. The top surface exhibits certain reoccurring morphological features, and variations in internal track melting boundaries are observed. Any observed cavities appear similar to those produced using the horizontal process, with the difference of their orientation. A combination of the horizontal and the near-vertical process could be beneficial; the near-vertical approach offers potential for shorter inter-layer time and the horizontal method for better surface finish than that of its counterpart. Potential benefits of, and improvements to, the near-vertical process are discussed.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Laser welding, Narrow Gap, Vertical Welding, Multi-Layer, Filler wire
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-74541 (URN)10.1016/j.optlastec.2019.105798 (DOI)000491217800032 ()2-s2.0-85072045298 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-09-20 (johcin)

Available from: 2019-06-14 Created: 2019-06-14 Last updated: 2019-11-06Bibliographically approved
Moradi, M., Meiabadi, S. & Kaplan, A. (2019). 3D Printed Parts with Honeycomb Internal Pattern by Fused Deposition Modelling: Experimental Characterization and Production Optimization. Metals and Materials International, 25(5), 1312-1325
Open this publication in new window or tab >>3D Printed Parts with Honeycomb Internal Pattern by Fused Deposition Modelling: Experimental Characterization and Production Optimization
2019 (English)In: Metals and Materials International, ISSN 1598-9623, E-ISSN 2005-4149, Vol. 25, no 5, p. 1312-1325Article in journal (Refereed) Published
Abstract [en]

In the present study additive manufacturing of Polylactic acid by fused deposition modeling were investigated based on statistical analysis. The honeycomb internal pattern was employed to build inside of specimens due to its remarkable capability to resist mechanical loads. Simplify 3D was utilized to slice the 3D model and to adjust fixed parameters. Layer thickness, infill percentage, and extruder temperature were considered as controlled variables, while maximum failure load (N), elongation at break (mm), part weight (g), and build time (min) were selected as output responses and analysed by response surface method. Analysis of variance results identified layer thickness as the major controlled variable for all responses. Interaction of infill percentage and extruder temperature had a significant influence on elongation at break and therefore, tough fracture of printed parts. The input parameters were optimized to materialize tow criteria; the first one was to rise maximum failure load and the second was to attain tough fracture and lessen build time and part weight at a time. Optimal solutions were examined by experimental fabrication to evaluate the efficiency of the optimization method. There was a good agreement between empirical results and response surface method predictions which confirmed the reliability of predictive models. The optimal setting to fulfill the first criterion could bring on a specimen with more than 1500 (N) maximum failure load and less than 9 (g) weight.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
3D printing, Fused deposition modelling, Mechanical properties, Part weight, Response surface method
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-73719 (URN)10.1007/s12540-019-00272-9 (DOI)000480764700019 ()2-s2.0-85070723837 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-08-30 (johcin)

Available from: 2019-04-23 Created: 2019-04-23 Last updated: 2019-08-30Bibliographically approved
Moradi, M., Arabi, H. & Kaplan, A. (2019). An experimental investigation of the effects of diode laser surface hardening of AISI 410 stainless steel and comparison with furnace hardening heat treatment. Journal of the Brazilian Society of Mechanical Sciences and Engineering, 41(10), Article ID 434.
Open this publication in new window or tab >>An experimental investigation of the effects of diode laser surface hardening of AISI 410 stainless steel and comparison with furnace hardening heat treatment
2019 (English)In: Journal of the Brazilian Society of Mechanical Sciences and Engineering, ISSN 1678-5878, E-ISSN 1806-3691, Vol. 41, no 10, article id 434Article in journal (Refereed) Published
Abstract [en]

This study investigated the ability of the continuous wave diode laser surface hardening of AISI 410 martensitic stainless steel with a maximum power of 1600 W. Variable process parameters scanning speed (4–7 mm/s), laser power (1200–1600 W) and stand-off distance (65–75 mm) were considered in this study. Microhardness, the geometry of hardened layer (depth and width), microhardness deviation from the base metal microhardness (MHD), microstructure analysis of the laser-hardened zone through optical microscopy and field emission scanning electron microscopy and percentage of the ferrite phase in AISI 410 microstructure by using Clemex software were considered as process output responses. Results confirmed that by increasing the laser power and reducing the scanning speed, the surface hardness and the depth of hardness increase. It is also revealed the width of the hardened area increases by enhancing stand-off distance and reducing the laser power. Maximum hardness of 630 HV0.3 with 2.2 mm depth is obtained. Also, the furnace hardening heat treatment is compared with the laser hardening process. Microstructure, microhardness, and impact tests of the two processes are compared. Results showed that the hardness of the diode laser is 1.4 times the hardness of the furnace hardening heat treatment.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Laser surface hardening, Diode laser, Microhardness, AISI 410 martensitic stainless steel, Microhardness deviation
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-76247 (URN)10.1007/s40430-019-1925-2 (DOI)000486507800004 ()2-s2.0-85073070504 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-10-04 (johcin)

Available from: 2019-10-04 Created: 2019-10-04 Last updated: 2019-10-21Bibliographically approved
Bunaziv, I., Akselsen, O., Frostevarg, J. & Kaplan, A. (2019). Application of laser-arc hybrid welding of steel for low-temperature service. The International Journal of Advanced Manufacturing Technology, 102(5-8), 2601-2613
Open this publication in new window or tab >>Application of laser-arc hybrid welding of steel for low-temperature service
2019 (English)In: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 102, no 5-8, p. 2601-2613Article in journal (Refereed) Published
Abstract [en]

Laser-arc hybrid welding (LAHW) is more often used in shipbuilding and oil and gas industries in recent years. Its popularity arises due to many advantages compared to conventional arc welding processes. The laser beam source is used to achieve much higher penetration depths. By adding filler wire to the process area, by means of an arc source, the mechanical properties can be improved, e.g. higher toughness at low temperatures. Therefore, LAHW is a perspective process for low-temperature service. Applicability of LAHW is under concern due to process stability and mechanical properties related to heterogeneous filler wire distribution through the whole weld metal in deep and narrow joints. This can cause reduced mechanical properties in the weld root as well as problems with solidification cracking. The fast cooling rate in the root provides hard and brittle microconstituents lowering toughness at low temperatures. Numerical simulations and experimental observations showed that an increase in heat input from the laser beam is an effective way to reduce the cooling rate, which is also possible by applying preheating.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Laser beam, Hybrid welding, Microstructure, Toughness, Numerical simulation
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-73054 (URN)10.1007/s00170-019-03304-1 (DOI)000469002200116 ()2-s2.0-85061037205 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-06-20 (johcin)

Available from: 2019-02-27 Created: 2019-02-27 Last updated: 2019-06-20Bibliographically approved
Bunaziv, I., Akselsen, O. M., Frostevarg, J. & Kaplan, A. (2019). Correction to: Application of laser-arc hybrid welding of steel for low-temperature service. The International Journal of Advanced Manufacturing Technology, 102(5-8), 2615-2615
Open this publication in new window or tab >>Correction to: Application of laser-arc hybrid welding of steel for low-temperature service
2019 (English)In: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 102, no 5-8, p. 2615-2615Article in journal (Refereed) Published
Abstract [en]

The original version of this article contained several mistakes. Due to technical problems at the typesetter, author corrections were not carried out. The original article has been corrected.

Place, publisher, year, edition, pages
Springer, 2019
Identifiers
urn:nbn:se:ltu:diva-73409 (URN)10.1007/s00170-019-03536-1 (DOI)
Note

The International Journal of Advanced Manufacturing Technology, 102, 5-8, 2601-2613, DOI: 10.1007/s00170-019-03304-1

Available from: 2019-04-03 Created: 2019-04-03 Last updated: 2019-06-20Bibliographically approved
Olsson, R., Powell, J., Palmquist, A., Brånemark, R., Frostevarg, J. & Kaplan, A. (2019). Formation of osseointegrating (bone integrating) surfaces on titanium by laser irradiation. Journal of laser applications, 31(2), Article ID 022508.
Open this publication in new window or tab >>Formation of osseointegrating (bone integrating) surfaces on titanium by laser irradiation
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2019 (English)In: Journal of laser applications, ISSN 1042-346X, E-ISSN 1938-1387, Vol. 31, no 2, article id 022508Article in journal (Refereed) Published
Abstract [en]

Pulsed lasers can be used to modify the surface of medical implants in order to accelerate bone growth (osseointegration). A surface covered in attached droplets with diameters between 1 and 20 μm is a beneficial surface for rapid osseointegration. This paper presents the results of an experimental program in which a broad range of laser parameters and different atmospheres were used to create different surface textures on titanium substrates, including the desired "attached droplet" topology. The resulting surfaces were analyzed by scanning electron microscopy and micro-computer tomography. The paper explains how different types of surfaces are created by the laser-material interaction under different conditions and focus characteristics. It is shown that optimization of the laser parameters results in a robust process, which produces a surface that is fundamentally different from those created by nonlaser methods.

Place, publisher, year, edition, pages
Laser Institute of America, 2019
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-73825 (URN)10.2351/1.5096075 (DOI)000484435200078 ()2-s2.0-85064218607 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-05-03 (johcin)

Available from: 2019-05-03 Created: 2019-05-03 Last updated: 2019-10-01Bibliographically approved
Näsström, J., Brueckner, F. & Kaplan, A. (2019). Laser enhancement of wire arc additive manufacturing. Paper presented at Proceedings of the International Congress of Applications of Lasers & Electro-Optics (ICALEO® 2018). Journal of laser applications, 31(2), Article ID 022307.
Open this publication in new window or tab >>Laser enhancement of wire arc additive manufacturing
2019 (English)In: Journal of laser applications, ISSN 1042-346X, E-ISSN 1938-1387, Vol. 31, no 2, article id 022307Article in journal (Refereed) Published
Abstract [en]

Additive manufacturing (AM) can be used for the fabrication of large metal parts, e.g., aerospace/space applications. Wire arc additivemanufacturing (WAAM) can be a suitable process for this due to its high deposition rates and relatively low equipment and operationcosts. In WAAM, an electrical arc is used as a heat source and the material is supplied in the form of a metal wire. A known disadvantageof the process is the comparably low dimensional accuracy. This is usually compensated by generating larger structures than desired andmachining away excess materials. So far, using combinations of arc in atmospheric conditions with high precision laser heat sources forAM has not yet been widely researched. Properties of the comparable cheap arc-based process, such as melt pool stability and dimensionalaccuracy, can be improved with the addition of a laser source. Within this paper, impacts of adding a laser beam to the WAAMprocess are presented. Differences between having the beam in a leading or a trailing position, relative to the wire and arc, are alsorevealed. Structures generated using the arc-laser-hybrid processes are compared to ones made using only an arc as the heat source. Bothgeometrical and material aspects are studied to determine the influences of laser hybridization, applied techniques including x ray,energy-dispersive X-ray spectroscopy, and high precision 3D scanning. A trailing laser beam is found to best improve topological capabilitiesof WAAM. Having a leading laser beam, on the other hand, is shown to affect cold metal transfer synergy behavior, promotinghigher deposition rates but decreasing topological accuracy.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2019
Keywords
additive manufacturing, laser augmentation, gas metal arc, hybrid processing, wire arc additive manufacturing/WAAM
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-74233 (URN)10.2351/1.5096111 (DOI)000484435200037 ()
Conference
Proceedings of the International Congress of Applications of Lasers & Electro-Optics (ICALEO® 2018)
Funder
Interreg Nord, 20200060
Note

Konferensartikel i tidskrift

Available from: 2019-06-07 Created: 2019-06-07 Last updated: 2019-10-01Bibliographically approved
Näsström, J., Brueckner, F. & Kaplan, A. (2019). Measuring the effects of a laser beam on melt pool fluctuation in arc additive manufacturing. Rapid prototyping journal, 25(3), 488-495
Open this publication in new window or tab >>Measuring the effects of a laser beam on melt pool fluctuation in arc additive manufacturing
2019 (English)In: Rapid prototyping journal, ISSN 1355-2546, E-ISSN 1758-7670, Vol. 25, no 3, p. 488-495Article in journal (Refereed) Published
Abstract [en]

Purpose

The steadily growing popularity of additive manufacturing (AM) increases the demand for understanding fundamental behaviors of these processes. High-speed imaging (HSI) can be a useful tool to observe these behaviors, but many studies only present qualitative analysis. The purpose of this paper is to propose an algorithm-assisted method as an intermediate to rapidly quantify data from HSI. Here, the method is used to study melt pool surface profile movement in a cold metal transfer-based (CMT-based) AM process, and how it changes when the process is augmented with a laser beam.

Design/methodology/approach

Single-track wide walls are generated in multiple layers using only CMT, CMT with leading and with trailing laser beam while observing the processes using HSI. The studied features are manually traced in multiple HSI frames. Algorithms are then used for sorting measurement points and generating feature curves for easier comparison.

Findings

Using this method, it is found that the fluctuation of the melt surface in the chosen CMT AM process can be reduced by more than 35 per cent with the addition of a laser beam trailing behind the arc. This indicates that arc and laser can be a viable combination for AM.

Originality/value

The suggested quantification method was used successfully for the laser-arc hybrid process and can also be applied for studies of many other AM processes where HSI is implemented. This can help fortify and expand the understanding of many phenomena in AM that were previously too difficult to measure.

Place, publisher, year, edition, pages
Emerald Group Publishing Limited, 2019
Keywords
Melt flow, Cold metal transfer, High speed imaging, Material deposition, Quantifying results
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-71688 (URN)10.1108/RPJ-01-2018-0033 (DOI)000464998000006 ()
Note

Validerad;2019;Nivå 2;2019-04-23 (oliekm)

Available from: 2018-11-21 Created: 2018-11-21 Last updated: 2019-06-14Bibliographically approved
Kaplan, A. F. ., Robertson, S. M., Frostevarg, J., Volpp, J., Ramasamy, A. & Kalfsbeek, B. (2019). Microstructure morphology characterization of welding consumables studied by pulse-shaped laser heating. Paper presented at 17th Nordic Laser Materials Processing Conference (NOLAMP17), 27-29 August, 2019, Trondheim, Norway. Procedia Manufacturing, 36, 184-191
Open this publication in new window or tab >>Microstructure morphology characterization of welding consumables studied by pulse-shaped laser heating
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2019 (English)In: Procedia Manufacturing, E-ISSN 2351-9789, Vol. 36, p. 184-191Article in journal (Refereed) Published
Abstract [en]

During welding, wire consumables can essentially contribute to the resulting microstructures and mechanical properties. In order to maintain high toughness even for high strength steel, certain microstructures are desirable, particularly acicular ferrite. An efficient, controllable test method was developed during which the wire is molten and experiences a thermal cycle by a shaped laser pulse, or a sequence of pulses, which shall resemble continuous laser-arc hybrid welding or narrow gap multi-layer laser welding. Different thermal cycles and wire chemistries have led to manifold microstructures. The morphology of the microstructures can become complex. Therefore, more detailed characterization of essential morphology aspects was carried out, to distinguish different results. The thermal cycles from quenching have led to shorter, thicker laths with more random orientation. The latter can be favourable for high toughness. Short reheating cycles by about 200 K/s caused finer, longer and more parallel laths, as for bainite, in varying size of blocks. Other aspects considered were grain boundary ferrite and non-metallic inclusions. Systematic variation of the thermal cycle by the testing method along with systematic description of microstructure morphology in more detail is a promising method to identify and optimize favoured routes for wire chemistry and welding techniques.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
weld, steel, microstructure, categorization, morphology, geometry, shape, systematics
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-75730 (URN)10.1016/j.promfg.2019.08.024 (DOI)
Conference
17th Nordic Laser Materials Processing Conference (NOLAMP17), 27-29 August, 2019, Trondheim, Norway
Note

Konferensartikel i tidskrift

Available from: 2019-08-28 Created: 2019-08-28 Last updated: 2019-08-28Bibliographically approved
Bunaziv, I., Frostevarg, J., Ren, X., Kaplan, A. & Akselsen, O. M. (2019). Porosity and solidification cracking in welded 45 mm thick steel by fiber laser-MAG process. Paper presented at 17th Nordic Laser Materials Processing Conference (NOLAMP17), 27-29 August, 2019, Trondheim, Norway. Procedia Manufacturing, 36, 101-111
Open this publication in new window or tab >>Porosity and solidification cracking in welded 45 mm thick steel by fiber laser-MAG process
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2019 (English)In: Procedia Manufacturing, E-ISSN 2351-9789, Vol. 36, p. 101-111Article in journal (Refereed) Published
Abstract [en]

Porosity and solidification cracking in joining of thick sections are very common issues in deep penetration keyhole laser-arc hybrid welding (LAHW). In the present work, 45 mm thick high strength steel was joined by a double-sided technique. With combined use of fast welding speeds and larger air gap between plates, higher amount of porosity was found because of the dynamic behavior of the keyhole walls. Solidification cracking formed at the centerline in the bottom of the weld due to high-depth-to-width geometrical ratio. Numerical simulations have been performed and showed very high cooling rate and stresses occurred in the root of the deep welds, which corresponds with higher cracking tendency.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Laser welding, hybrid welding, solidification cracking, porosity, thick steel, mechanical properties
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-75764 (URN)10.1016/j.promfg.2019.08.015 (DOI)
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: 2019-08-29Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-3569-6795

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