The use of holographic optics for heat flow optimisation in wire V8.pdf (1.14 MB)
Download fileThe use of holographic optics for heat flow control in wire-based laser cladding
conference contribution
posted on 2015-02-27, 11:37 authored by Nick Goffin, Shuai Hou, John TyrerJohn Tyrer, Rebecca HigginsonRebecca HigginsonLaser cladding with wire utilises a focussing lens to melt the surface of the substrate, into which the wire is fed to build up a clad track on the surface. Process reliablity issues in practice include; clad tracks with high levels of dilution, surface cracking and other defects. Key to this is wire reflectivity calculations. Here using Fresnel equations that relate angle of incidence to heat absorption, we are able to show a direct correlation between the applied heat profile of the laser beam and the absorption profile of the wire surface; this has been modelled using COMSOL multiphysics conduction simulations which showed that the heat profile of the applied laser beam has a direct effect on the size and shape of the resulting melt pool. Using computer generated Holographic Optical Elements (HOE), a novel form of optic that alters the heat profile of the laser beam to a user-specified 3d profile, a conventional 1.25 mm diameter Gaussian beam shape and a 1.25 mm square uniform ‘pedestal’ HOE-derived beam shape were tested and compared, using a 1 mm diameter AISI 316 stainless steel wire on a 0.8mm mild steel substrate. These results were also compared to an enlarged 3.5 mm diameter Gaussian beam, in order to evaluate different methods of altering the heat distribution applied to the wire. The HOE generated beam gave superior results, due to its shorter thermal cycle, which reduced the amount of heat going into the clad track and resulted in lower dilution.
History
School
- Mechanical, Electrical and Manufacturing Engineering
Published in
ICALEOPages
383 - 392Citation
GOFFIN, N.J., 2014. The use of holographic optics for heat flow control in wire-based laser cladding. IN: The 33rd International Congress on Applications of Lasers & Electro-Optics (ICALEO) Congress Proceedings, San Diego, 19-23 October 2014, pp. 383 - 392.Publisher
ICALEO 2014 Proceedings © Laser Institute of AmericaVersion
- AM (Accepted Manuscript)
Publisher statement
All rights reservedPublication date
2014Notes
This paper was presented at ICALEO 2014. Further information is available at: http://icaleo2014.conferencespot.org/ISBN
9781940168029Language
- en