Application of high speed filming techniques to the study of rearwards melt ejection in laser drilling

Jones, Connor and Hann, David B. and Voisey, K.T. and Aitken, Scott (2017) Application of high speed filming techniques to the study of rearwards melt ejection in laser drilling. Journal of Laser Applications, 29 (2). 022204/1-022204/9. ISSN 1042-346X

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Abstract

Melt ejection is the dominant material removal mechanism in long, ms, pulse laser drilling of metals, a process with applications such as the drilling of cooling holes in turbine blades. Droplets of molten material are ejected through the entrance hole and, after breakthrough, through the exit hole. High speed filming is used to study the ejected material in order to better understand how this debris may interact with material in the immediate vicinity of the drilled hole. Existing studies have quantified various aspects of melt ejection, however they usually focus on ejection through the entrance hole. This work concentrates on rear melt ejection and is relevant to issues such as rear wall impingement. A 2kW IPG 200S fibre laser is used to drill mild steel. High speed filming is combined with image analysis to characterise the rearward-ejected material. Particle size and velocity data is presented as a function of drilling parameters. It is concluded that high speed filming combined with image analysis and proper consideration of process limitations and optimisation strategies can be a powerful tool in understanding resultant debris distributions.

Item Type: Article
Additional Information: Paper given at International Congress on Applications of Lasers & Electro-Optics (ICALEO), San Diego, USA, 16-20 October 2016
Keywords: laser drilling, melt ejection, high speed filming, high speed imaging, particle tracking, velocity measurement, image analysis
Schools/Departments: University of Nottingham, UK > Faculty of Engineering > Department of Mechanical, Materials and Manufacturing Engineering
Identification Number: 10.2351/1.4983269
Depositing User: Jones, Connor
Date Deposited: 24 Aug 2016 10:18
Last Modified: 18 Oct 2017 17:48
URI: http://eprints.nottingham.ac.uk/id/eprint/35999

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