lnu.sePublikationer
Ändra sökning
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Experimental and Theoretical Investigation of the Laser Cutting Process
2015 (Engelska)Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

This thesis concerns experimental investigations of laser cutting with theoretical and practical discussions of the results. The thesis is made up of three papers which are linked in such a way that each of them studies a different aspect of laser cutting: In paper I the two major laser types in cutting, namely CO2 and fiber lasers, are compared to each other by a self-defined cut efficiency. Next in paper II the laser cutting process is observed with a high speed imaging, HSI, camera to give information about the melt flow in the cut zone. In paper III the initiation of the laser cutting process, called piercing, is studied. Paper I is about investigating the effect of material type, material thickness, laser wavelength, and laser power on the efficiency of the cutting process for industrial state-of-the-art cutting machines. Here the cutting efficiency is defined in its most fundamental terms: as the area of cut edge created per Joule of laser energy. This paper presents phenomenological explanations for the relative cutting efficiencies of fiber lasers and CO2 lasers and the mechanisms affecting these efficiencies for stainless steels and mild steel over a range of thicknesses. The paper also involves a discussion of both theoretical and practical engineering issues.In Paper II a new experimental technique has been developed which enables High Speed Imaging of laser cut fronts produced using standard, commercial parameters. The results presented here suggest that the cut front produced when cutting 10 mm thick medium section stainless steel with a fibre laser and a nitrogen assist gas is covered in humps which themselves are covered in a thin layer of liquid. A combination of HSI results and theoretical analysis has revealed that these humps move down the cut front at an average speed which is a factor three less than the liquid flow speed. Paper III addresses a specific topic: Before any cut is started the laser needs to pierce the material. The two most important aspects of the piercing process are: a) How long does it take to pierce the material? And b) How wide is the pierced hole? If the hole is no wider than the cut line, the material can be pierced on the line to be cut. In this paper the laser piercing process is investigated using a wide range of laser pulse parameters, for stainless steel using a fibre laser, to discover their influence on pierce time and pierced hole diameter. A high speed imaging camera is used to time the penetration event and to study the laser-material interactions involved in drilling the pierced holes. Optimum parameters have been identified for both pierce time and pierce hole width.

Ort, förlag, år, upplaga, sidor
2015: Luleå University of Technology, 2015.
Serie
Licentiate thesis / Luleå University of Technology, ISSN 1402-1757
Nationell ämneskategori
Bearbetnings-, yt- och fogningsteknik
Forskningsämne
Teknik, Maskinteknik
Identifikatorer
URN: urn:nbn:se:lnu:diva-111361Libris ID: 19462177ISBN: 9789175834665 (tryckt)ISBN: 9789175834672 (digital)OAI: oai:DiVA.org:lnu-111361DiVA, id: diva2:1652169
Tillgänglig från: 2022-04-15 Skapad: 2022-04-15 Senast uppdaterad: 2022-04-27Bibliografiskt granskad

Open Access i DiVA

Fulltext saknas i DiVA

Övriga länkar

Fulltext

Person

Pocorni, Jetro Kenneth

Sök vidare i DiVA

Av författaren/redaktören
Pocorni, Jetro Kenneth
Bearbetnings-, yt- och fogningsteknik

Sök vidare utanför DiVA

GoogleGoogle Scholar

isbn
urn-nbn

Altmetricpoäng

isbn
urn-nbn
Totalt: 64 träffar
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf