Additive manufacturing of technical ceramics

• Autor(a) principal: Silva, António Miguel Rocha Raimundo
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.8/4021
• topic: FDC; Filament; Feedstock; Binder; Powder; WC-10Co; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Eletrotécnica, Eletrónica e Informática

Additive Manufacturing (AM) is an area intrinsically linked to industry 4.0 because of its ability to meet some of the most significant challenges in the industry such as production of custom parts, complex geometries and direct processing (through cloud manufacturing). Due to its advantages, the market for functional parts based on inorganic materials via AM is in great development. The present study has focused on the Fused Deposition of Ceramics (FDC) process, which is suitable, in combination with post-processing steps such as debinding and sintering, for the consolidation of ceramic powder particles from filamentary materials. Although the volume content of ceramic powders is very limited, due to the absence of high pressures, the FDC has been of scientific and industrial interest due to its ability to eliminate some limitations imposed by other processes such as Selective Laser Melting (SLM), due to the sources of high energy consumption, and Powder Injection Molding (PIM), due geometric and mold cost limitations. The major challenges of this dissertation involved producing filaments for FDC, based on PIM or powder extrusion (PE) methodologies, joining the filaments of feedstock with optimized ratios of tungsten carbide powder (48.5%vol.) that should withstand the stresses involved in the FDC extrusion, and providing suitable extrusion fluidity. Afterwards, the challenges were overcome and the shaped parts through FDC were debinded and sintered. These processes led to the production of near net shape WC-10Co parts with characteristics and properties close to those resulting from conventional replicative processes of the powders.