Mestrados da ESTG
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Browsing Mestrados da ESTG by Subject "3D Printing"
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- 3D Printing of raw earth composites – Effect of low environmental impact binder on the process and material propertiesPublication . Fahfouhi, Karim; Bártolo, Helena Maria Coelho da Rocha Terreiro Galha da Silva; Craveiro, Flávio Gabriel da SilvaThe rapid rate of climate change is increasingly affecting our everyday life and disrupting the economy worldwide. The global construction industry is a major CO₂ emitter and a huge consumer of natural resources and energy. Sustainability is a major concern, so the construction sector must minimize its impact on the environment, embracing a radical transformation by minimizing its impact on the environment, addressing this way the climate emergency. Europe is committed to being the first carbon-neutral continent, promoting environmental and social change by addressing the challenges of becoming more resilient, sustainable, and socially inclusive. Over centuries, raw earth construction materials and techniques have been used to build houses, mainly due to their minimal carbon footprint, low thermal conductivity, and good hygroscopic properties. Natural fibers were added to the earth matrix to improve its performance. Today, there is a rising interest in earthen composites as a building material, mainly due to their many advantages in comparison with conventional construction materials. Using local materials can reduce embodied energy in the transportation and storage of materials. Earth-based materials are also better suited for the environment. The need to advance the green transition towards a more circular economy is driving the construction sector towards a more efficient use of energy, natural resources, and materials, incorporating low embodied carbon materials and new technologies. Construction has been experiencing a digital revolution by incorporating new technologies and construction processes, such as Additive Manufacturing (AM), also called 3D Printing (3DP). The integration of 3DP into construction processes will allow for greater flexibility in design and customization, with the emergence of complex shapes and new materials, as well as reducing costs, time and waste. However, digital fabrication in construction is still evolving, holding great potential for future construction automation, and presenting several advantages over conventional construction technologies and processes. The development of material compositions with appropriate flowability, extrudability, buildability, to meet the 3-D printing process requisites is still a major challenge for the application of 3-D printing. In this research work, different earth-based composites and binders were investigated, on processing aspects and properties, for future digital extrusion.
- Evaluation of Mechanical Properties of Fused Filament Fabrication 3D Printed PartsPublication . Bento, Catarina Cortez; Vasco, Joel Oliveira Correia; Freitas, Dino Miguel FernandesThis report was based on the project at Aalen University in the scope of the curricular subject of the thesis, inserted in the study program of the master’s degree in Mechanical Engineering – Industrial Production. The project had a duration of six months. The project goal was to study the manufacturing process of metal parts using Fused Filament Fabrication (FFF). The FFF is a technique in which a fused filament is deposited controlled over or adjoining previous deposited filaments, leading to the construction of a structural part. To realize the evaluation of mechanical properties of FFF three dimensional (3D) printed parts it was performed in four main tasks: First, specimens were printed at 0º with three different infill patterns (gyroid, tri-hexagon, and quarter cubic) and two different infill densities (25% and 40%). The printing of these specimens was intended to perform density tests, tensile tests, and roughness tests. Secondly, small cubes with the same infill density (100%) were printed but with different infill patterns (gyroid, tri-hexagon, and quarter cubic) so that it was possible to compare the roughness on the different faces of the cube. These infill patterns and infill densities were chosen, to complement studies previously done by other colleagues. Third, 0°, 45°, and 90° specimens were printed with support structures to perform the charpy v test. However, performing these tests was impossible because the debinding and sintering company could not deliver the parts in time. At last, a cost analysis of the FFF process and the Selective Laser Melting (SLM) process in the production of a compressor turbine was made. With the tests performed throughout this study, it was possible to conclude that the debinding and sintering process influences the weight of the specimens and the infill density and pattern have an influence on the mechanical behaviour of the specimens.
- Methodologies for pre-processing polymeric filament for Direct Digital FabricationPublication . Silva, César Miguel Coitos da; Correia, Mário António Simões; Coelho, Paulo Jorge SimõesThe digital age presents alternatives to more traditional manufacturing concepts. One of the alternatives most adopted by the industry and society, in general, focuses on additive manufacturing, which has improved significantly over time, improving the user interface and optimizing parts construction times and quality. In this work is intended to study the impact of dehumidification pre-processing of the material at the Polylactic Acid (PLA) and Polyethylene Terephtalate Glycol (PETG), used in Fused Deposition Modeling (FDM). The results obtained in on the parts produced allowed to draw conclusions about impacts at an aesthetic level and at a mechanical level, and assess whether the pre-processing energy costs are justified, regarding the final quality of the produced part or improvements in their mechanical properties. Measurements of the weight were carried out on the printed pieces for the aesthetic experiments to compare the printed piece with dehumidified, non-dehumidified material, the Computer-Aided Design (CAD) part simulation and slicer software part simulation. The most significant results occurred in the aesthetic tests, as the differences are evident between the part printed with dehumidified material and the part printed with non-dehumidified material. The final weight of the pieces differs in all scenarios, where the lightest pieces are in the CAD software simulation, and heaviest parts are in the simulation of the slicer software. In the tensile tests, the non-dehumidified PLA material obtained better performance when compared to the PLA that was previously dehumidified for 6 hours. In the case of PETG, it was possible to identify the similar tensile strength between the previously dehumidified filament and the filament not previously dehumidified. To conclude the energy study revealed an overall consumption of approximately 0.32 kWh for the dehumidifier and printer set.