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Computational control of laser systems for micro-machining

Issa, Ahmed A.A. (2007) Computational control of laser systems for micro-machining. PhD thesis, Dublin City University.

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Depending on the size and geometry, laser-microfabricated structures in transparent materials have applications in telecommunications, microfluidics, micro-sensors, data storage, glass cutting and decorative marking applications. The relations of Nd:YV04 and C02 laser system parameter settings to the dimensions and morphology of microfabricated structures were examined in this work. Laser system parameters investigated included power, P, pulse repetition frequency, PRF, number of pulses, N, and scanning speed, U. Output dimensions measured included equivalent voxel diameter as well as microchannel width, depth and surface roughness. A 3D microfabrication system was developed using the Nd:YV04 laser (2.5 W, 1.064 pm, 80 ns) to fabricate microstructures inside polycarbonate samples. Microstructure voxels ranged from 48 to 181 pm in diameter. Tight focusing was also achieved with this system using a microscope objective lens to produce smaller voxels ranging from 5 to 10 pm in soda-lime glass, fused silica and sapphire samples. The C02 laser (1.5 kW, 10.6 pm, minimum pulse width of 26 ps) was used to fabricate microchannels in soda-lime glass samples. The cross-sectional shapes of the microchannels varied between v-shape grooves, u-shaped groves and superficial ablated regions. Microchannels dimensions also varied with widths ranging from 81 to 365 pm, depths ranging from 3 to 379 pm and surface roughness between 2 to 13 pm being produced depending on the process settings. The microchannel dimensions were studied in terms of the laser processing parameters using the response surface methodology (RSM) with the design of experiments technique (DOE). The collected results were used to study the effect of the process parameters on the volumetric and mass ablation rates. Moreover, a thermal mathematical model of the process was also developed in order to aid understanding of the process and to allow channel topology prediction a priory to actual fabrication.

Item Type:Thesis (PhD)
Date of Award:2007
Supervisor(s):Brabazon, Dermot and Hashmi, Saleem
Uncontrolled Keywords:microfabricated structures; microfabrication; Microstructure voxels
Subjects:Engineering > Materials
Engineering > Mechanical engineering
DCU Faculties and Centres:DCU Faculties and Schools > Faculty of Engineering and Computing > School of Mechanical and Manufacturing Engineering
Use License:This item is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 3.0 License. View License
ID Code:16930
Deposited On:30 Apr 2012 16:32 by Fran Callaghan. Last Modified 25 Nov 2016 16:30

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