EDM performance of electroformed Cu‐ZrB₂ shell electrodes

Abstract

Purpose

Cu‐ZrB₂ shell electrodes were fabricated by composite electroforming to improve the spark‐resistance of the electrical discharge machining (EDM) electrodes made by rapid tooling.

Design/methodology/approach

Cu‐ZrB₂ shell electrodes were fabricated using composite electroforming, separating and backing. EDM performance evaluation of the Cu‐ZrB₂ shell electrodes is performed using tool steel as the cathode workpiece and the Cu‐ZrB₂ composite as the anode tool. The effects of ZrB₂ content on the electrode and workpiece removal rate, wear ratio of the electrode to workpiece, and surface quality of workpiece and electrode were studied.

Findings

Compared with the conventional electroformed copper tools, Cu‐ZrB₂ shell electrodes yield higher workpiece removal rate and lower tool wear ratio. Scanning electron microscopy (SEM) and electron microprobe analysis reveal that, due to the large difference between the melting point of ZrB₂ and copper, the heat generated by the sparks is conducted mainly through the copper matrix, reducing the erosion of ZrB₂ particles. The refractory ZrB₂ particles then act as barriers to the flowing and outburst of melted copper and enhance the resistance to erosion of the electrodes.

Originality/value

The use of Cu‐ZrB₂ shell electrodes improves the anti‐erosion properties of the EDM electrodes made by rapid tooling, especially in finish machining conditions. Such electrodes will not only reduce the failure of the EDM electrodes but also improve the machining precision due to the less dimension loss of the electrodes during machining.

Citation

Zhang, M., Guo, D. and Jin, Z. (2009), "EDM performance of electroformed Cu‐ZrB₂ shell electrodes", Rapid Prototyping Journal, Vol. 15 No. 2, pp. 150-156. https://doi.org/10.1108/13552540910943450