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2014
Conference Paper
Titel
Evaluation of gap control strategies in jet electrochemical machining on defined shape deviations
Alternative
Evaluierung von Strategien der Arbeitsspaltregelung bei der elektrochemischen Bearbeitung mit Jet-ECM anhand definierter Formabweichungen
Abstract
Jet Electrochemical Machining (Jet-ECM) is an innovative micro-production technique for machining complex and highly accurate geometries in electrically conductive materials [1, 2, 3]. In Jet-ECM a continuous electrolytic free jet is used in which extremely high current densities up to 2000 A/cm² can be applied [4]. Figure 1 shows a schematic illustration of the Jet-ECM principle. The electrolytic solution is pumped continuously through a micro nozzle, which usually has a diameter of 100 µm. The electrolyte is ejected with an average speed of approximately 20 m/s perpendicularly to the work piece surface. Thus a free jet is formed on the surrounding atmospheric air, which leads to a highly localized current density and to a highly localized machining area. Micro structures are actually machined by moving the nozzle horizontally over the work piece surface and switching the process voltage in dependence of the nozzle's position. For this purpose a prototype setup based on a three-axes positioning system was designed and realized [5]. The electrolytic jet can be seen as an ohmic resistor, whereat the value of resistance is proportional to the length of the jet and thus changes according to the actual working gap. Hence, the actual current density depends on the actual working gap, which directly influences the shape of the eroded structures. For this reason several strategies for gap control in Jet Electrochemical Machining were analysed [6] and implemented in the LabVIEW-based control software of the prototype setup.