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Fresnel absorption ...
Fresnel absorption of 1 μm- and 10 μm-laser beams at the keyhole wall during laser beam welding : Comparison between smooth and wavy surfaces
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- Kaplan, Alexander (författare)
- Luleå tekniska universitet,Produkt- och produktionsutveckling
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(creator_code:org_t)
- Elsevier BV, 2012
- 2012
- Engelska.
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 258:8, s. 3354-3363
- Relaterad länk:
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- The angle-dependent absorption of laser beams at metal surfaces is described by the Fresnel-equations. During keyhole laser welding the essential interaction takes place at very striping angles of incidence of the order of 1-8 degrees at the front of the vapour capillary, called the keyhole. For a smooth vapour capillary, laser beams with a wavelength of about 1 μm operate in a Fresnel-regime where the absorptance increases with the angle of incidence at the wall, towards the weak Brewster-angle maximum. In contrast, for 10 μm-lasers high absorptance around the more pronounced Brewster-angle peak takes place. From high speed imaging keyhole surface waves were observed. Mathematical modelling of the laser-keyhole interaction demonstrates that already relatively little waviness of the melt surface at the keyhole strongly modulates the angles of incidence and in turn the Fresnel-absorption due to varying angles of incidence, soon also leading to shadow zones. Due to this local variation of the angle of incidence the absorptance tends towards the angle-averaged value, with the consequence that for 1 μm-lasers the direct absorptance and in turn the penetration depth increases, particularly at low welding speed, while for 10 μm-lasers it generally decreases.
Ämnesord
- TEKNIK OCH TEKNOLOGIER -- Materialteknik -- Bearbetnings-, yt- och fogningsteknik (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Materials Engineering -- Manufacturing, Surface and Joining Technology (hsv//eng)
Nyckelord
- Produktionsutveckling
- Manufacturing Systems Engineering
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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