This presentation covers 3 recent developments at the Laser Processing Research Centre (LPRC), University of Manchester, in the area of laser processing of engineering materials comprising (1) elimination of striation in laser cutting, (2) large area laser nano-patterning and texturing; and (3) high efficiency laser generation of nano particles.
Part I: Elimination of striation in laser cutting of mild steel sheets
Periodical lines have always existed in laser cut surfaces in metallic and ceramic materials. These are termed striation. They affect surface finishes and accuracy of geometry. Although scientists have made significant efforts to model the process, until now, no practical solution for the elimination of striation has been found. This recent work developed at LPRC has demonstrated a new approach in the successful elimination of striation in laser cutting of mild steel sheets. Both experimental and theoretical studies will be presented.
Topic (1): Large area laser nano-patterning and texturing
Laser nano-patterning of surfaces requires the overcoming of the diffraction limit of the lasers. Focused ion beams and electron beams are much better placed for precision nano-patterning over small areas. For large area nano patterning, parallel writing would be more desirable and difficult to achieve using focused ion beams and electron beams. This work recently developed at the LPRC demonstrates a technique for laser writing of over 6 million nano lines and complex patterns simultaneously.
Topic (2): High efficiency laser generation of nano particles
There is a large number of methods for the generation of nano particles. Among these, chemical processes are most popular for their high productivity and low cost. However, they produce unwanted chemical products and the particle size distribution is wide. Laser based processes (e.g. decomposition of gases, and ablation of solid and powdered targets) have been found to be able to produce better quality nano particles (higher purity, narrower size distribution and less wastes). However, laser means are costly and have very low productivity and energy efficiency. Recent work at the LPRC has shown a new approach in laser generation of nano particles (TiO2) that significantly improves the production rate (comparable to chemical methods) and energy efficiency.
About the Speaker
Professor Lin Li holds a chair of Laser Engineering at the University of Manchester. He is the Director of Laser Processing Research Centre (LPRC) and the Head of Manufacturing and Laser Processing Research Group, which has a total manpower strength of 70 staff and PhD researchers.
Professor Li obtained a PhD degree in laser processing from Imperial College in 1989. He began his career with Liverpool University laser laboratory for 6 year before joining University of Manchester Institute of Science and Technology (UMIST) as a faculty member in 1994. He was promoted to full Professorship in 2000. His research interests include laser drilling, laser cutting, laser welding, micro-machining, nano-manufacturing, synthesis of novel materials, surface engineering and rapid prototyping and additive manufacturing. He is a member of the Editorial Board of journal Optics and Laser Technology, member of Executive Committee of Association of Industrial Laser Users, Fellow of Institute of Engineering and Technology, Fellow of Laser Institute of America, Director of Northwest Laser Engineering Consortium in the UK, Director of Roll-Royce Laser Technology Partnership, and SIMTech Visiting Fellow.
Currently, Professor Li's laser laboratory is equipped with 16 high power laser processing systems with the widest range of laser facilities for materials processing in the UK. The LPRC has currently, a research team of 30 research scientists. Professor Li is author/co-author of over 400 publications with over 200 in peer reviewed journals. The work by LPRC has received Charles Mains Award, Sir Frank Whittle Award and UK House of Commons Best Engineer of the Year Award. The current research projects in LPRC are funded by over £3 million external research contracts.
3.00pm: Presentation (Part I): Laser Cutting
3.35pm: Q & A Session
3.45pm: Refreshment & Networking
4.00pm: Presentation (Part II): Laser Nano-fabrication
4.35pm: Q & A
5.00pm: End of Presentation
Who Should Attend
Researchers, academic staff, industry professionals and students of tertiary institutions.
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