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The use of holographic optics for heat flow control in wire-based laser cladding

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conference contribution
posted on 27.02.2015 by Nick Goffin, Shuai Hou, John Tyrer, Rebecca Higginson
Laser 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

ICALEO

Pages

383 - 392

Citation

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 America

Version

AM (Accepted Manuscript)

Publisher statement

All rights reserved

Publication date

2014

Notes

This paper was presented at ICALEO 2014. Further information is available at: http://icaleo2014.conferencespot.org/

ISBN

9781940168029

Language

en

Location

San Diego

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