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AVALIAÇÃO DE TÉCNICAS NÃO DESTRUIVAS PARA A INSPEÇÃO DE COMPONENTES PRODUZIDOS POR WAAM: ULTRASSONS E CORRENTES INDUZIDAS
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O Wire Arc Additive Manufacturing (WAAM) é um processo de fabrico aditivo que tem suscitado interesse a nível da investigação. A implementação deste processo na indústria está dependente do sucesso da aplicação dos Ensaios não Destrutivos (END), algo que ainda acarreta algumas dificuldades. Os END são métodos que permitem identificar e avaliar defeitos em materiais sem danificar os componentes
O objetivo deste trabalho consistiu em desenvolver sondas de Ultrassons e Correntes Induzidas para inspecionar componentes produzidos por WAAM inline.
Para tal, foram criadas sete sondas de ultrassons direitas, com sete piezoelétricos diferentes. Realizou-se uma caracterização para cada etapa de construção das sondas. Foi efetuada uma prova de conceito para cada sonda, bem como ensaios por contacto e por imersão em cordões de WAAM hot-forging. Procedeu-se à conceção e à caracterização de duas sondas de correntes induzidas absolutas, e à realização de ensaios com estas sondas em peças WAAM com defeitos.
Os resultados obtidos demonstraram que as sondas de ultrassons por contacto não permitiram a deteção de defeitos, enquanto nos ensaios por imersão isso foi possível. Com as correntes induzidas foram identificados defeitos fabricados que consistiam num furo de 2mm de diâmetro, embora com baixa relação sinal-ruído. Estes resultados mostram a necessidade de desenvolvimento de outras sondas, com um maior número de bobinas em diferentes direções.
Wire Arc Additive Manufacturing (WAAM) is an additive manufacturing process that has raised research interest. The implementation of this process in industry is dependent on the successful application of non-destructive testing (NDT), something that still entails some difficulties. NDT are methods that allow the identification and evaluation of defects in materials without damaging the components. The objective of this work was to develop Ultrasonic and eddy Current probes to inspect components produced by inline WAAM. To this end, seven straight ultrasonic probes were created, with seven different piezoelectrics. A characterization was performed for each stage of construction of the probes. A proof of concept was carried out for each probe, as well as contact and immersion tests on WAAM hot-forging strands. Two absolute eddy current probes were designed and characterized, and tests were performed with these probes on defective WAAM parts. The results obtained showed that the contact ultrasonic probes did not allow the detection of defects, while in the immersion tests this was possible. With the eddy currents, fabricated defects consisting of a 2mm diameter hole were identified, although with a low signal-to-noise ratio. These results show the need for the development of other probes, with a larger number of coils in different directions.
Wire Arc Additive Manufacturing (WAAM) is an additive manufacturing process that has raised research interest. The implementation of this process in industry is dependent on the successful application of non-destructive testing (NDT), something that still entails some difficulties. NDT are methods that allow the identification and evaluation of defects in materials without damaging the components. The objective of this work was to develop Ultrasonic and eddy Current probes to inspect components produced by inline WAAM. To this end, seven straight ultrasonic probes were created, with seven different piezoelectrics. A characterization was performed for each stage of construction of the probes. A proof of concept was carried out for each probe, as well as contact and immersion tests on WAAM hot-forging strands. Two absolute eddy current probes were designed and characterized, and tests were performed with these probes on defective WAAM parts. The results obtained showed that the contact ultrasonic probes did not allow the detection of defects, while in the immersion tests this was possible. With the eddy currents, fabricated defects consisting of a 2mm diameter hole were identified, although with a low signal-to-noise ratio. These results show the need for the development of other probes, with a larger number of coils in different directions.
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Wire Arc Additive Manufacturing (WAAM) Ensaios Não Destrutivos (END) Correntes Induzidas (CI) Ultrassons (US) Defeitos