Additive manufacturing (AM) technology is not only used to make 3D objects but also for rapid prototyping. In industry and laboratories, quality controls for these objects are necessary though difficult to implement compared to classical methods of fabrication because the layer-by-layer printing allows for very complex object manufacturing that is unachievable with standard tools. Furthermore, AM can induce unknown or unexpected defects. Consequently, we demonstrate terahertz (THz) imaging as an innovative method for 2D inspection of polymer materials. Moreover, THz tomography may be considered as an alternative to x-ray tomography and cheaper 3D imaging for routine control. This paper proposes an experimental study of 3D polymer objects obtained by additive manufacturing techniques. This approach allows us to characterize defects and to control dimensions by volumetric measurements on 3D data reconstructed by tomography.
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http://dx.doi.org/10.1364/AO.55.003462 | DOI Listing |
RSC Adv
January 2025
LSRE-LCM - Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials, Faculty of Engineering, University of Porto Rua Dr Roberto Frias 4200-465 Porto Portugal
Additive Manufacturing (AM) was evaluated as a promising technology for constructing photocatalytic reactors due to its inherent ability to produce complex geometries with high precision and customization. In this work, a 3D structure was designed to achieve a good light distribution inside a cylindrical batch reactor and printed using the stereolithography (SLA) technique. A hybrid material composed of a commercial photoreactive resin (Formlabs Clear V4) and the benchmark photocatalyst TiO P25 Evonik (1 wt%) was prepared and characterized by scanning electron microscopy (SEM) and rheological and mechanical methods.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Karlsruhe Institute of Technology KIT, Institute for Chemical Technology and Polymer Chemistry, Kaiserstr. 12, Fakultät für Chemie, 76131, Karlsruhe, GERMANY.
In the frame of developing a sustainable chemical industry, heterogeneously catalyzed CO2 hydrogenation to methanol has attracted considerable interest. However, the Cu-Zn based catalyst system employed in this process is very dynamic, especially in the presence of the products methanol and water. Deactivation needs to be prevented, but its origin and mechanism are hardly investigated at high conversion where product condensation is possible.
View Article and Find Full Text PDFAdv Mater
January 2025
Department of Materials Science and Engineering, University of Pennsylvania, 3231 Walnut Street, Philadelphia, PA, 19104, USA.
Cholesteric liquid crystal elastomers (CLCEs) hold great promise for mechanochromic applications in anti-counterfeiting, smart textiles, and soft robotics, thanks to the structural color and elasticity. While CLCEs are printed via direct ink writing (DIW) to fabricate free-standing films, complex 3D structures are not fabricated due to the opposing rheological properties necessary for cholesteric alignment and multilayer stacking. Here, 3D CLCE structures are realized by utilizing coaxial DIW to print a CLC ink within a silicone ink.
View Article and Find Full Text PDFSci Rep
January 2025
Advanced Manufacturing Lab, ETH Zürich, Leonhardstrasse 21, 8092, Zurich, Switzerland.
The rapid advancements in additive manufacturing (AM) across different scales and material classes have enabled the creation of architected materials with highly tailored properties. Beyond geometric flexibility, multi-material AM further expands design possibilities by combining materials with distinct characteristics. While machine learning has recently shown great potential for the fast inverse design of lattice structures, its application has largely been limited to single-material systems.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Materials Science and Engineering, College of Engineering, City University of Hong Kong, Hong Kong, China.
Ordered intermetallic alloys are renowned for their impressive mechanical, chemical, and physical properties, making them appealing for various fields. However, practical applications of them have long been severely hindered due to their severe brittleness and poor fabricability. It is difficult to fabricate such materials into components with complex geometries through traditional subtractive manufacturing methods.
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