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Title: Pulsed laser drilling of engineering materials
Author: Hodgett, David Lowry
Awarding Body: University of Birmingham
Current Institution: University of Birmingham
Date of Award: 1970
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The development of a high mean power laser, designed as a prototype for future machine tools, is described. The laser operating characteristics are measured and the output calibrated by means of a cone calorimeter and a photo-diode monitor. The cone calorimeter is compared with two commercially available calorimeters. The cooling of laser cavities is discussed and a theoretical treatment of the liquid cooling of high mean power pulsed lasers developed. The drilling process is investigated both theoretically and experimentally. The theoretical treatment proposes that liquid ejection is the principal means of mass removal and examines the two most probable causes of liquid ejection. The relevant thermophysical properties of liquid metals are collated and theoretical and empirical methods for the prediction of those properties not yet experimentally determined are outlined. High speed photography is used to investigate the ejection of material during drilling. Two distinct types of ejecta are identified and their velocities measured by streak and schlieren photography. Further, the influence of impurities within the metal on the drilling performance is investigated in an attempt to determine whether nucleation is the prime cause of liquid ejection. Finally, the most useful directions of research and development are suggested and further experiments are described which would add considerably to the evidence available on the drilling mechanism and thereby help to improve drilling performance.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available