Day 1 :
Ishlinsky Institute for Problems in Mechanics - RAS, Russia
Time : 09:30-10:10
Prof. Manzhirov is a well-recognized scientist working in the field of mechanics and applied mathematics. Currently he is Deputy Director of the Ishlinsky Institute for Problems in Mechanics of the Russian Academy of Sciences and Head of the Department for Modeling in Solid Mechanics at the same institute. He is the author of more than 250 scientific publications, including sixteen books and four textbooks. His main scientific activities concern mechanics of growing solids, additive manufacturing technologies, contact mechanics and tribology, viscoelasticity and creep theory. He is also universally known as an author of the world’s first fundamental handbooks on integral equations.
Additive Manufacturing (AM) technologies are an exciting area of the modern industrial revolution and have applications in instrumentation, engineering, medicine, electronics, aerospace industry, and other fields. They include stereolithography, electrolytic deposition, thermal and laser-based 3D printing, 3D-IC fabrication technologies, etc. and are booming nowadays owing to their ability to fabricate products with unique characteristics that cannot be made with traditional fabrication techniques. AM enables cost-effective production of customized geometry and parts by direct fabrication from 3D data and mathematical models. However, to further the progress in the emerging area and empower scientists, engineers, and designers to fully implement the novel processes' capabilities, there is a need for a systematic study of mechanical analysis for AM technologies. Despite much progress in the area of AM technologies, problems of mechanical design and analysis for AM fabricated parts yet remain to be solved. So far, three main problems can be isolated: (i) the onset of residual stresses, which inevitably occur in the manufacturing process and can lead to failure of the parts, (ii) the distortion of the final shape of AM fabricated parts, and (iii) the development of technical and technological solutions aimed at improving existing AM technologies and creating new ones. We propose a fundamental approach for the modeling of surface growth of solids, which effectively describes the deformation processes in AM fabricated parts, as well as analytical and numerical methods for its implementation. This material is based upon work financially supported by the Russian Science Foundation under Grant No. 17-19-01257.
Aix Marseille University, France
Frederic Dumur has completed his PhD from Angers University (France) in 2002. From 2003 to 2008, he was successively a Postdoctoral Fellow in the group of Professor Ben L. Feringa (2003-2005), Nobel Prize 2016, Dr. Norbert Hoffmann (Reims, France), and Professor Francis Sécheresse (Versailles, France). Since 2008, he is Associate Professor at the Institute of Radical Chemistry of Aix Marseille University. He has published more than 180 papers in international journals. Frédéric Dumur is specialized in the design of organocatalysts and metal complexes as photoinitiators of polymerization under soft irradiation conditions.
Light induced cationic polymerization (CP) and free radical polymerization (FRP) reactions in the presence of a photoinitiator (PI) have been largely encountered for a long time in the radiation curing area. Today, due to their decisive advantages (low heat generation, low energy consumption, low operating costs, less maintenance, long life, portability, compact design, easy and safe handling, possible incorporation in robots or 3D printers, etc.), many developments are related to the use of Light Emitting Diode (LED) arrangements as excitation sources instead of the traditional mercury lamps or even lasers. Particularly, applications in the violet spectral range require LEDs operating at 365, 385, 395 or 405 nm. One of the key points is still the matching between the PI absorption and the LED emission spectrum. This condition is easily fulfilled with a lot of radical PIs.
Diaryliodonium and triarylsulfonium salts and others have been extensively studied as PIs. However, the starting structures are characterized by an absorption in the UV region (230–300 nm). The design of novel high-performance cationic PIs directly adapted to violet or visible LED irradiation is still challenging. Here, we present a novel photosensitive iodonium salt resulting from a coupling between naphthalimide and diphenyliodonium moieties (Figure 1) being able to work under LED exposure at 365, 385 and 395 nm without any additive and to initiate the cationic polymerization of diepoxides, divinylethers as well as diepoxide/divinyether blends and also the FRP of methacrylates.
MATEIS (UMR CNRS 5510), France
Keynote: Robocasting of dense ceramic parts
Time : 11:05-11:45
L. Gremillard has completed his engineering degree and PhD from INSA-Lyon. After a 2-years post-doctoral fellowship at Lawrence Berkeley National Laboratory, he was appointed a scientist at CNRS (France) in the Materials Science and Engineering Laboratory (MATEIS) at INSA-Lyon. He is now Senior Researcher at CNRS, and head of the Biological Interactions and Biomaterials team of MATEIS. He is mostly known for his work on zirconia as a biomaterial. He has published more than 65 papers in reputed peer-reviewed, international journals and has been serving as a symposium organiser of ESB2016 and EUROMAT 2017.
Additive manufacturing of ceramic has known a large expansion over the past few years, mostly for its ability for creating 3D complex ceramic bodies with controlled porosity. Robocasting, or direct-ink writing, is one of the techniques available for ceramic additive manufacturing. It implies the extrusion through a nozzle of a self-setting paste in the shape of a filament to create the desired shape, layer by layer. One of the great interests of this technique is the possibility to fabricate multimaterials in one single printing step, using multiple pastes. This include both porouse, architecture pieces and dense bodies. However, shaping dense bodies (from either single or multiple inks) is still a challenge not completely met by additive manufacturing in general and direct ink writing in particular, since the properties obtained by conventional processing have not yet been successfully reproduced.
The aim of this presentation is to demonstrate the correlation between printing parameters (nozzle diometer, inter-filaments distance, printing velocity, environment…), paste fabrication (solid loading, binder, solvent, mixing, degassing, rheology…), thermal treatments (drying, debinding), defects distribution and mechanical properties in final sintered bodies.
We’ll show that printing precision, pattern design, layer-to-layer spacing and substrate adhesion play a critical role on the quality of the final piece, in a way that is far more important for ceramics than for polymers and metals. An optimization of all steps of the robocasting process enables the fabrication of dense high-strength materials with mechanical properties similar to those obtained by conventional processing.