SUNConferences, COMA '13

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Study of Pulse Electrochemical Machining of Nickel-Cobalt Ferrous Alloy
Dirk Bähre, Olivier Weber, Andreas Rebschläger, Philipp Steuer

Last modified: 2013-08-20


Kovar, also known by the brand names Dilvar P1 or Pernifer 2918, is a controlled expansion alloy made of 29% Nickel, 17% Cobalt and the remaining balance is Iron. The expansion characteristics of Kovar match both borosilicate glasses and alumina ceramics, making it one of the most popular of the controlled expansion alloys for hermetic sealing or deep-drawing. Furthermore, Kovar is also used in applications such as power tubes, microwave tubes, transistors, diodes, hybrid packages and other scientific instruments. However, the processing of Kovar by conventional manufacturing processes is very difficult because the material is resilient and mild. The tools tend to plow the alloy instead of cutting into it. In this study, the potential of Pulse Electrochemical Machining (PECM) for the machining of Kovar is investigated. As an alternative procedure to conventional manufacturing technologies like turning, milling or grinding, PECM can be applied to machine this material. The geometry of the cathode is reproduced on the workpiece by electrolytic material removing without any contact with the tool. Therefore the material removal characteristics of Kovar with PECM are determined by performing systematic design of experiments techniques applying an industrial PECM machine system (PEMCenter8000) to fulfil the effective utilization of the process and minimize the number of trials. An analysis of the precision of the manufactured geometries and the possibility of generating defined surface qualities are contents of this study.

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