A4 Conference proceedings

Controlled metal transfer from a wire by a laser-induced boiling front


LUT Authors / Editors

Publication Details
Authors: Kaplan Alexander, Torkamany Mohammad Javad, Ghaini Malek, Vänskä Mikko, Salminen Antti, Fahlström Karl, Hedegård Joakim
Publication year: 2015
Language: English
Title of parent publication: Proceedings of the Lasers in Manufacturing (LiM) Conference 2015
JUFO-Level of this publication: 0
Open Access: Not an Open Access publication

Abstract
The addition of wire is an option during laser welding, laser cladding or laser additive manufacturing. By high speed imaging of leading wire addition during fibre laser keyhole welding it was observed that for the 40 experiments under consideration the wire tip always established a concave boiling front. The front appears similar to a keyhole front and is sort of a continuation of the keyhole, owing to the leading wire employment. For most of the parameters the melt is transferred downwards from the wire tip into the melt pool surrounding the keyhole front. In other words, hardly any uncontrolled spatter to the sides was observed. A trailing wire would normally tend to a completely different behaviour. Typical as well as limiting phenomena of the wire melt transfer mechanism are presented and discussed. Controlled vertical melt transfer of the wire through the ablation pressure from a laser-induced boiling front, either in contact with the workpiece surface or positioned higher above, can be a desirable mechanism of metal deposition for the different techniques, namely welding, surface treatment or LAM. By suitable choice of the laser power density above the boiling threshold, the here observed mechanism can be applied in a controllable manner. An interesting technique option is lateral beam oscillation for example by a galvanometer optics which shears off the melt in a manner similar to remote fusion cutting. The process limits become different to the static technique. The wire melt transfer technique has the potential to be developed further towards a highly controllable remote drop transfer, e.g. in terms of direction.

Last updated on 2017-27-03 at 11:36