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Inovação tecnológica do processo WAAM com vibração mecânica do banho de fusão
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O processo Wire and Arc Additive Manufacturing (WAAM) é uma tecnologia de
Fabrico Aditivo (FA) que permite produzir peças com desperdício de material reduzido
e elevadas taxas de deposição. No entanto, é necessário um conhecimento mais
profundo do processo para melhorar a qualidade superficial, propriedades mecânicas e
diminuição da ocorrência de defeitos.
O principal objetivo desta dissertação foi estudar o efeito da vibração mecânica do
banho de fusão, com vista a promover um refinamento da microestrutura e melhorar as
propriedades mecânicas em peças produzidas com aço inoxidável ER316L e magnésio
AZ61A.
Foi desenvolvido um protótipo funcional que permitiu produzir amostras variando a
frequência, amplitude e movimento de vibração. Avaliaram-se os efeitos da vibração
mecânica na geometria e na microestrutura das amostras. Realizaram-se ensaios de
microdureza, condutividade elétrica e termografia. Foi medida a temperatura com
termopares e captados vídeos do processo em câmara lenta.
Conclui-se que o protótipo desenvolvido permitiu a realização de peças por WAAM
com vibração no banho de fusão. Nas amostras de ER316L a nucleação aumentou 47%
e o comprimento das dendrites diminuiu 44%. Nas amostras de AZ61A o tamanho de
grão diminuiu 59%. Tanto a frequência como a amplitude não afetaram
significativamente a altura e largura das paredes, no entanto, as ondulações periódicas
tornaram-se 20% menores a 10 Hz de frequência e 2 mm de amplitude. A vibração não
foi suficiente para provocar uma diminuição significativa da condutividade elétrica ou da
dureza nas amostras.
Wire and Arc Additive Manufacturing (WAAM) is an Additive Manufacturing (AM) technology that produces parts with reduced material waste and high deposition rate. However, a deeper knowledge of the process is needed to improve surface quality, mechanical properties and decrease defects. The main objective of this dissertation was to study the effect of the mechanical vibration of the melting pool, in order to promote grain refinement and improve the mechanical properties in parts produced with stainless steel ER316L and magnesium AZ61A. A functional prototype was developed that produced the variation in frequency, amplitude and type of vibration. The effects of mechanical vibration on geometry and microstructure are evaluated. Microhardness, electrical conductivity and thermography tests were carried out. The temperature was measured with thermocouples and videos of the process were captured in slow motion. It is concluded that the developed prototype allowed the realization of parts by WAAM with vibration in the melting pool. In ER316L samples, nucleation increased 47% and dendrite length decreased 44%. In the samples of AZ61A the grain size decreased by 59%. Both the frequency and the amplitude did not affect complementing the height and width of the walls, however, as periodic ripples become 20% finer at 10 Hz frequency and 2 mm amplitude. The vibration was not sufficient to cause a decrease in electrical conductivity or hardness in the configurations.
Wire and Arc Additive Manufacturing (WAAM) is an Additive Manufacturing (AM) technology that produces parts with reduced material waste and high deposition rate. However, a deeper knowledge of the process is needed to improve surface quality, mechanical properties and decrease defects. The main objective of this dissertation was to study the effect of the mechanical vibration of the melting pool, in order to promote grain refinement and improve the mechanical properties in parts produced with stainless steel ER316L and magnesium AZ61A. A functional prototype was developed that produced the variation in frequency, amplitude and type of vibration. The effects of mechanical vibration on geometry and microstructure are evaluated. Microhardness, electrical conductivity and thermography tests were carried out. The temperature was measured with thermocouples and videos of the process were captured in slow motion. It is concluded that the developed prototype allowed the realization of parts by WAAM with vibration in the melting pool. In ER316L samples, nucleation increased 47% and dendrite length decreased 44%. In the samples of AZ61A the grain size decreased by 59%. Both the frequency and the amplitude did not affect complementing the height and width of the walls, however, as periodic ripples become 20% finer at 10 Hz frequency and 2 mm amplitude. The vibration was not sufficient to cause a decrease in electrical conductivity or hardness in the configurations.
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Wire and Arc Additive Manufacturing vibração protótipo funcional banho de fusão microestrutura aço inoxidável e magnésio