ChemEng.Upatras Seminars 2022 - Nickolas D. Polychronopoulos
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Abstract
Additive Manufacturing (AM) is regarded as one of the pillars of Industry 4.0 and aims at layer-by-layer fabrication of parts with high geometrical complexity. Among a dozen of different AM technologies, Selective Laser Sintering (SLS) and melt extrusion (popularly known as 3D Printing) are the most promising. While these innovative techniques have lately gained a lot of attention, their use as regular production technologies is still limited, due to three major problems: (i) narrow variety of applicable materials, (ii) void formation between the adjacent layers leading to inferior mechanical properties and (iii) low-to-moderate production rates. To address these issues, a fundamental understanding of the processes is absolutely necessary. The present lecture will demonstrate how the combined use of modeling, computer flow simulations and rheological analysis can aid towards improved designs of equipment, processes and parts. Examples will include mathematical modeling of coalescence of spheres (SLS), cylinders (melt extrusion) and computer simulation of screw extrusion in concrete 3D printing.
Speakers Short CV
Dr. Nickolas D. Polychronopoulos holds a B.Sc. in Materials Science (Univ. Patras) and an M.Sc and PhD in Mechanical Engineering (Univ. Thessaly). He currently works for Polydynamics Inc (Ontario, Canada) as a Research & Development Engineer on modeling and applications in polymer processing and additive manufacturing. He has worked at Rontis Hellas S.A. (Larissa), a medical devices company, for a year and he has been a post-doc in the Centre for Research & Technology Hellas (CERTH) for a research project concerning the magnetic guidance and bio-heat transfer of nanofluids to tumors. He has more than ten years of experience in modeling, computer simulations and rheological analysis for flows of non-Newtonian polymers in complex channels, composites, particle coalescence and heat transfer. He has published 15 research articles in peer-reviewed journals including Soft Matter, Polymers, Rheologica Acta, Rapid Prototyping Journal and Transport in Porous Media, 5 book chapters and co-authored a textbook. He has presented lectures in Canada, USA, Germany, Austria, France, Belgium and Netherlands. He has taught two times in Univ. Thessaly (Dept. Mech Eng., Volos) the course “Rheology and Processing of Polymers” and he is currently teaching in the same university (Dept. Energy Systems, Larissa) the course “Advanced Fluid Mechanics Machines” focusing on pumps, rheology and flow modeling in extrusion-based 3D printing.