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7370 |
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Friday, May 06, 2022, Hall G2 2:20 PM Characterization & Testing Methods II |
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Evaluation of electric conductivity and mechanical load capacity of copper deposits for application in large winding components for electrical high-voltage machines made with cold spray additive manufacturing |
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Thomas Braun* / Technische Universität Berlin, Germany Eckart Uhlmann / Institute for Machine Tools and Factory Mangement, Technische Universität Berlin, Germany Jan Kondas/ Impact Innovations GmbH, Germany Ralf Häcker/ Bundesanstalt für Materialforschung und –prüfung (BAM), Germany Hartmut Rauch/ Siemens AG, Germany Markus Jäger/ Institute of Energy and Automation Technology, Technische Universität Berlin, Germany Karsten Brach/ Siemens AG, Germany Reeti Singh/ Impact Innovations GmbH, Germany |
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In line with the industrial trend of additive manufacturing, cold spray as a non-laser-based process is becoming increasingly important for many fields of application. For the evaluation of additive manufacturing of winding components made of copper for large electrical high-voltage machines, material and component properties such as electrical conductivity, mechanical load capacity and the component size that can be produced are of particular importance. In this context, the cold spray process offers advantages over laser-based additive manufacturing processes such as laser powder bed fusion (LPBF) or laser cladding by using the kinetic energy of the copper powder particles to generate particle cohesion. To investigate the electrical conductivity as well as the mechanical load capacity of cold spray parts, specimens were machined out of cold sprayed bulk copper deposits. The characteristic values were obtained with regard to the direction of deposition, which is defined by the direction of the robot’s movement. Thus, for the investigation of the component properties, specimens were provided that had been produced both longitudinally and transversely as well as orthogonally to the direction of deposition. The results of the investigations show that both the electrical conductivity and the mechanical load capacity of the specimen have a strong preferential direction of the specimen orientation with respect to the direction of deposition. Furthermore, it could be shown that by increasing the deposition height, there is an increasing oxygen content in the sample material, combined with increasingly significant defect networks. These effects have a negative impact on the electrical conductivity as well as on the mechanical load capacity. As a conclusion, further need for investigation is identified in the optimization of the process parameters as well as in the deposition strategy for the additive manufacturing of large-volume components with cold spray. |