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Publications (10 of 309) Show all publications
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
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 2005-4149Article in journal (Refereed) Epub ahead of print
Abstract [en]

In the present study additive manufacturing of Polylactic acid by fused deposition modeling were investigated based on statis-tical 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
Other Mechanical Engineering
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-73719 (URN)10.1007/s12540-019-00272-9 (DOI)
Available from: 2019-04-23 Created: 2019-04-23 Last updated: 2019-04-23
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
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 1433-3015Article in journal (Refereed) Epub ahead of print
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
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)
Available from: 2019-02-27 Created: 2019-02-27 Last updated: 2019-04-03
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
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 1433-3015Article in journal (Refereed) Epub ahead of print
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, Volume, Issue, StartPage-EndPage, DOI: 10.1007/s00170-019-03304-1

Available from: 2019-04-03 Created: 2019-04-03 Last updated: 2019-04-09
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)
Note

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

Available from: 2018-11-21 Created: 2018-11-21 Last updated: 2019-04-23Bibliographically approved
Siva Prasad, H., Frostevarg, J. & Kaplan, A. (2019). The stability of laser welding with an off-axis wire feed. Journal of Materials Processing Technology, 264, 84-90
Open this publication in new window or tab >>The stability of laser welding with an off-axis wire feed
2019 (English)In: Journal of Materials Processing Technology, ISSN 0924-0136, E-ISSN 1873-4774, Vol. 264, p. 84-90Article in journal (Refereed) Published
Abstract [en]

The concept using an off-axis filler wire during laser welding is introduced here in order to provide added process robustness considering gap width variations. Its stability is investigated with respect to gap width, welding speeds and powers. Geometry of the welds is analysed by tracing of weld cap edges and joint cross sections, connecting trends to weld parameters. High speed imaging and streak images are used to further study and describe sequences of events, including undercut formation. Formation of imperfections are found to be mainly correlated to wire feed position variations at the surface due to irregular melting of the wire tip.

Place, publisher, year, edition, pages
Elsevier, 2019
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-70826 (URN)10.1016/j.jmatprotec.2018.09.003 (DOI)000450135400009 ()2-s2.0-85053062410 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-09-21 (svasva)

Available from: 2018-09-11 Created: 2018-09-11 Last updated: 2018-12-05Bibliographically approved
Samarjy, R. S. M. & Kaplan, A. (2018). Additive manufacturing and recycling by a laser-induced drop jet from a sheet edge. Journal of laser applications, 30(4), Article ID 042010.
Open this publication in new window or tab >>Additive manufacturing and recycling by a laser-induced drop jet from a sheet edge
2018 (English)In: Journal of laser applications, ISSN 1042-346X, E-ISSN 1938-1387, Vol. 30, no 4, article id 042010Article in journal (Refereed) Published
Abstract [en]

A new technique for additive manufacturing was recently presented by depositing droplets as a continuous track on a substrate, where the droplets were ejected from laser remote fusion cutting of a metal sheet. For the here presented approach, the droplets are instead ejected from the sheet edge, termed the machining mode, which is compared to cutting. Here, the transmitted part of the laser beam does not hit and interact with the deposited track because of lateral dislocation. High speed imaging has shown that laser-induced boiling, which drives the melt downwards, causes asymmetric conditions in the machining mode by lateral pushing of the generated drop jet under the sheet, where the melt can even attach. Compared to machining, the cutting mode keeps less deviation of the drop trajectories, higher precision, and a smoother surface finish. It was demonstrated that the edge conditions after machining are sufficient to repeat the process. This enables additional technique opportunities, including recycling of a whole sheet of waste metal. By the aid of high speed imaging from two different perspectives, the melt flow behavior, the drop jet precision, and process trends with respect to parameters, drop ejection, and deposition were studied.

Keywords
additive manufacturing; melt drop ejection; laser-induced ablation; high speed imaging; metal recycling
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-71870 (URN)10.2351/1.5026202 (DOI)000451729800011 ()2-s2.0-85057063428 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-12-03 (inah)

Available from: 2018-12-03 Created: 2018-12-03 Last updated: 2019-01-24Bibliographically approved
Näsström, J., Frostevarg, J. & Kaplan, A. (2018). Arc formation in narrow gap hot wire laser welding. Welding Journal, 97(6), 171S-178S
Open this publication in new window or tab >>Arc formation in narrow gap hot wire laser welding
2018 (English)In: Welding Journal, ISSN 0043-2296, Vol. 97, no 6, p. 171S-178SArticle in journal (Refereed) Published
Abstract [en]

Many heavy industrial applications, e.g. shipbuilding and offshore, rely on thick-section, high-quality welds. Unfortunately, traditional arc-based techniques are often found wanting due to a limited penetration depth and excessive heat-affected zone. The former is typically solved by having a wide groove filled by multiple weld passes, which is both costly and time consuming. Other processes such as autonomous laser or electron beams can join thick materials, but have disadvantages such as increased hardness and solidification cracks inside the welds. A promising in-between technique to join thick sheets is narrow gap multi layer laser welding (NGMLW), using less filler material while also offering more control of weld properties. This technique is often used with laser scanning optics and cold wire, or a defocused laser and electrically heated wire. This paper investigates the limitations of the latter during NGMLW, mainly using high-speed imaging to directly observe and explain process behavior. Increased deposition rates are wanted, but heating also consequently needs to be increased for proper bead fusion. Arc occurrences are found to be the cause of instabilities. They are observed occasionally even at low voltages, but more frequently at higher outputs, and then are also more disruptive to the process.

Place, publisher, year, edition, pages
American Welding Society, 2018
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-70165 (URN)10.29391/2018.97.015 (DOI)000435429400018 ()2-s2.0-8504937533 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-07-26 (inah)

Available from: 2018-07-26 Created: 2018-07-26 Last updated: 2018-08-09Bibliographically approved
Volpp, J., Prasad, H. S. & Kaplan, A. (2018). Behavior of heated powder particles on solid surfaces. Paper presented at 8th Swedish Production Symposium, SPS 2018, Stockholm, Sweden, 16-18 May 2018.. Procedia Manufacturing, 25, 365-374
Open this publication in new window or tab >>Behavior of heated powder particles on solid surfaces
2018 (English)In: Procedia Manufacturing, E-ISSN 2351-9789, Vol. 25, p. 365-374Article in journal (Refereed) Published
Abstract [en]

Powder particles applied through a powder nozzle as used e.g. in laser additive manufacturing or cladding processes are heated during their flight through the laser beam. The heating process and the interaction of the particle with the solid substrate were modeled in this work. In addition, the particle interaction with the solid substrate was observed using high speed imaging. At a high temperature and a high speed of the particles, the heat conduction into the base material is not fast enough to solidify the particles due to the short interaction time with the substrate.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-70242 (URN)10.1016/j.promfg.2018.06.105 (DOI)
Conference
8th Swedish Production Symposium, SPS 2018, Stockholm, Sweden, 16-18 May 2018.
Note

Konferensartikel i tidskrift;2018-08-07 (andbra)

Available from: 2018-08-07 Created: 2018-08-07 Last updated: 2018-09-11Bibliographically approved
Bunaziv, I., Akselsen, O. M., Frostevarg, J. & Kaplan, A. F. .. (2018). Deep penetration fiber laser-arc hybrid welding of thick HSLA steel. Journal of Materials Processing Technology, 256, 216-228
Open this publication in new window or tab >>Deep penetration fiber laser-arc hybrid welding of thick HSLA steel
2018 (English)In: Journal of Materials Processing Technology, ISSN 0924-0136, E-ISSN 1873-4774, Vol. 256, p. 216-228Article in journal (Refereed) Published
Abstract [en]

The present investigation addresses laser-arc hybrid welding of 45 mm thick steel with variation in a wide range of process parameters. High volume fraction of acicular ferrite formed in the upper part of the weld metal regardless process parameters. Significantly lower fraction of acicular ferrite was found in the root due to substantially increased cooling rates and the inability to deliver filler wire to this region, resulting in bainite-martensite microstructures in the root. The delivery of filler wire to the root can be enhanced by increasing the air gap between the plates. Higher heat inputs reduce cooling rates in the root which create softer and ductile microstructures, at the expense of a much wider and coarser grained HAZ. The results obtained showed high fusion line and weld metal toughness at low temperature (−50 °C).

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-67696 (URN)10.1016/j.jmatprotec.2018.02.026 (DOI)000431156800021 ()2-s2.0-85042446378 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-02-26 (andbra)

Available from: 2018-02-20 Created: 2018-02-20 Last updated: 2018-06-11Bibliographically approved
Pocorni, J., Powell, J., Frostevarg, J. & Kaplan, A. F. H. (2018). Dynamic laser piercing of thick section metals. Optics and lasers in engineering, 100, 82-89
Open this publication in new window or tab >>Dynamic laser piercing of thick section metals
2018 (English)In: Optics and lasers in engineering, ISSN 0143-8166, E-ISSN 1873-0302, Vol. 100, p. 82-89Article in journal (Refereed) Published
Abstract [en]

Before a contour can be laser cut the laser first needs to pierce the material. The time taken to achieve piercing should be minimised to optimise productivity. One important aspect of laser piercing is the reliability of the process because industrial laser cutting machines are programmed for the minimum reliable pierce time. In this work piercing experiments were carried out in 15 mm thick stainless steel sheets comparing a stationary laser and a laser which moves along a circular trajectory with varying processing speeds. Results show that circular piercing can decrease the pierce duration by almost half compared to stationary piercing. High speed imaging (HSI) was employed during the piercing process to understand melt behaviour inside the pierce hole. HSI videos show that circular rotation of the laser beam forces melt to eject in opposite direction of the beam movement, while in stationary piercing the melt ejects less efficiently in random directions out of the hole.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Laser cutting, laser piercing, reliability, efficiency, fibre laser, high speed imaging
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-63492 (URN)10.1016/j.optlaseng.2017.07.012 (DOI)000414108700010 ()2-s2.0-85026484330 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-08-15 (andbra)

Available from: 2017-05-23 Created: 2017-05-23 Last updated: 2019-02-18Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-3569-6795

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