Thesis Format
Monograph
Degree
Master of Engineering Science
Program
Mechanical and Materials Engineering
Supervisor
O. Remus Tutunea-Fatan
2nd Supervisor
Evgueni V. Bordatchev
Affiliation
National Research Council of Canada, London, Canada
Abstract
Laser polishing (LP) is a finishing technique used to enhance the quality of the workpiece surface. LP relies on laser radiation to melt a thin superficial layer of material in order to either smoothen the surface or generate structures on it. The process of surface smoothening is achieved via surface polishing utilizing laser remelting (SP-LRM). The process of structure generation is achieved via surface structuring by means of laser remelting (SS-LRM). The working distance of the laser beam is typically defined as the location of the focal point of the laser beam with respect to the top of the workpiece. The ability to change the working distance of the laser beam offers LP several advantages compared to conventional machining techniques by making the beam a flexible energy delivery tool. This thesis will focus on the development of a parametric model capable to classify and optimize the laser parameters used for surface polishing. Multiple laser-remelted lines were created with different combinations of laser power, feed rate, and working distances. The results show the importance of including the working distance as an essential process parameter since it can change the applied areal remelting power delivered to the surface of the workpiece. Furthermore, this study shows the existence of an optimal range of laser-remelted power to be used in the surface polishing process.
Summary for Lay Audience
Laser polishing (LP) is a finishing technique used in manufacturing to enhance the quality of the workpiece surface. It relies on laser radiation to melt a thin superficial layer of material in order to smoothen the surface or to generate structures on it. The final shape and quality are influenced by its initial surface topography and other process parameters such as laser speed, power, or working distance. Unlike manual superfinishing techniques, LP can be automated, making it an efficient finishing technique. More specifically, by changing the location of the focal point, the amount of laser energy delivered to the material can be controlled more precisely such that the laser can be regarded as a flexible energy depositing tool. This project aims to create a parametric analysis to be used to model and predict the final surface shape and quality. The analysis seeks to calculate the lateral distribution of the surface roughness and laser track profiles and find their statistical relationship to the energy density distribution delivered to the workpiece. The experimentally obtained results will be analyzed using in-house developed MATLAB algorithms to analyze and recognize specific features of 3D surface topography and use them for further statistical evaluation, classification, and recognition. With the proposed methodology, a new scientific and engineering understanding of the laser-material interactions will be implemented to optimize the LP process and predict/control desired surface quality. Future applications of these results can be applied with artificial intelligence (AI) techniques to optimize the selection of the process parameters in order to achieve the intended surface quality outcomes.
Recommended Citation
Meshreqy, Samer, "Parametric Modeling, Analysis, Classification, and Optimization of the Laser Polishing Process with Respect to the Working Distance" (2022). Electronic Thesis and Dissertation Repository. 9067.
https://ir.lib.uwo.ca/etd/9067