Electropulsing to assist conventional manufacturing processes

Resumen

This thesis presents a study on the variation of the mechanical properties of some materials. These variations are registered for processes as bottom bending, wire drawing or round turning, which are performed under high density electropulses. This research implied the study of several issues related to the manufacturing processes and the electric pulses. For example, some isolated systems are developed for each process. This is required for protecting the monitoring devices and machinery from electric drifts. On the other hand, several electropulse generators are designed and manufactured to electrically assist the aforementioned manufacturing processes. The electrical connectors is the main technological issue in each process to ensure good electrical contact during experimentation. Once the manufacturing setup is under control, electropulses are applied on various materials whilst its physical properties are measured and recorded. In particular, the processes are achieved under different electric configurations to infer the influence of the electropulses. The obtained results show that different mechanical and manufacturing properties like elastic restoring forces, yield strength, power consumption, surface roughness and material hardness among others are modified when the manufacturing process is assisted with a pulsed electric field. Additionally, the machinability and formability is improved when the metallic material is affected by current pulses. However, it should be noted that the mechanical properties behavior under different electrical parameters, like current density, frequency discharge and pulse duration, is complex and does not follow an expected relationship. Furthermore, numerical simulation analyses is required to study and understand the complex behavior of the mechanical properties. The manufacturing process of bending, machining and drawing process was done at the Universitat Politècnica de Catalunya (Spain) in collaboration with the Northwestern University (USA), the Universidad Pontificia Universidad Católica de Chile (Chile) and the Universidad Tecnológica de Pereira (Colombia). This thesis is funded by the Ministry of Economy and Competitiveness of Spain, reference project: DPI2011-26326 (grant no. BES-2012-056760). Along the document detailed information on methodology for the aforementioned processes and some conclusions are provided