Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Laser-induced boiling and melt transfer from a metal edge
Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.ORCID iD: 0000-0002-4569-8970
Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.ORCID iD: 0000-0002-3569-6795
2017 (English)In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197Article in journal (Refereed) Submitted
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 even can 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 behaviour, the drop jet precision as well as process trends with respect to parameters, drop ejection and deposition were studied.

Place, publisher, year, edition, pages
Elsevier, 2017.
Keyword [en]
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: urn:nbn:se:ltu:diva-64442OAI: oai:DiVA.org:ltu-64442DiVA: diva2:1114538
Note

In the thesis

Interaction mechanisms for a laser-induced metallic boilling front

Available from: 2017-06-24 Created: 2017-06-24 Last updated: 2017-11-24
In thesis
1. Interaction mechanisms for a laser-induced metallic boiling front
Open this publication in new window or tab >>Interaction mechanisms for a laser-induced metallic boiling front
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis is about fundamental interaction mechanisms of laser remote fusion cutting, RFC, which is based on the formation of a quasi-stationary laser-induced boiling front that causes drop ejection, preferably downwards. Laser cutting of metals, invented in 1967, has developed from a niche to a well established high quality cutting technique in the manufacturing industry. Usually a gas jet is employed concentric to the laser beam, to eject the molten metal. One technique option, interesting though hardly applied yet because of usually low quality and speed, is remote laser cutting. Two techniques are distinguished, remote ablation cutting, grooving down through a sheet, layer-by-layer, and the here addressed remote fusion cutting, by a single pass through the sheet. For the latter, the ablation pressure from laser-induced boiling at the cutting front continuously accelerates and ejects the melt downwards. Advantages of remote laser cutting, facilitated by high brilliance lasers during the last decade, are the possibility of a larger working distance along with the avoidance of cutting gas and of a gas jet nozzle.

 

The review paper of the thesis surveys different laser remote cutting techniques, including their modelling, as well as the transition to keyhole welding, owing to similarities particularly from the boiling front and from root spatter ejection. The six Papers I-VI that compose the thesis address fundamental mechanisms of laser remote fusion cutting, theoretically and experimentally. In Paper I a simplified mathematical model of the RFC cutting front enables to estimate the geometrical and energetic conditions of the process. By evidence and post-modelling from high speed imaging, HSI, the simplified smooth cutting front model is developed further to a wavy topology in Paper III, for more sophisticated absorption analysis. As a systematic support, Paper II categorizes and analyses for the first time the different wavy topologies observed at the front, from HSI. The melt dynamics induced by a pulsed laser beam was studied in Paper IV, again from HSI. Apart from other interesting transient melt phenomena it was demonstrated that the ablation pressure can push the melt to a certain pending position during the laser pulse while the melt retreats by surface tension during the pulse break. To engage remote fusion cutting with additive manufacturing, Paper V introduces a novel technique where the drops ejected from RFC are transferred to a substrate, about a centimetre underneath, on which a continuous track forms. This technique can even be applied as an efficient recycling approach. In Paper VI a variant of the technique is presented, to develop a boiling front along the edge of a metal sheet from which the drop transfer takes place, in a different manner. This enables to systematically machine-off the entire sheet, which can be converted to a new shape and product.

 

Summarizing, the thesis provides a variety of analysis of fundamental mechanisms of a laser-induced boiling front that bear a certain simplicity and in turn controllability, of interest for established as well as for new applications, in manufacturing and in other sectors, including remote fusion cutting.

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2017
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
Keyword
Laser remote fusion cutting, Boiling front, High speed imaging, Additive manufacturing, Ejection, Absorption, Wavy surface, Deposition
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-65281 (URN)978-91-7583-945-5 (ISBN)978-91-7583-946-2 (ISBN)
Public defence
2017-11-09, E632, Luleå University of Technology,S-97187, Luleå, 08:30 (English)
Opponent
Supervisors
Available from: 2017-08-28 Created: 2017-08-28 Last updated: 2017-11-24Bibliographically approved

Open Access in DiVA

No full text

Authority records BETA

Samarjy, Ramiz Saeed MattiKaplan, Alexander F.H.

Search in DiVA

By author/editor
Samarjy, Ramiz Saeed MattiKaplan, Alexander F.H.
By organisation
Product and Production Development
In the same journal
Materials & design
Manufacturing, Surface and Joining Technology

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 184 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf