Structuring of wear-affected copper electrodes for electrical discharge machining using Pulse Electrochemical Machining

•A two-stage process-chain is proposed for structuring hard metal with complex geometries.•The machining behavior of copper in PECM using sodium nitrate is investigated.•Copper is structured with four different geometries.•The reproducibly structured copper serves as tool for EDM.•We show that the reproduction of the initial tool strongly depends on the geometry to be copied.

The wear in electrical discharge machining exerts a great influence on the result and quality of the workpiece being machined. Especially complex structures can lead to high costs for electrode preparation. In this investigation a process chain is set up using copper electrodes machined by Pulse Electrochemical Machining for structuring hard metal by die-sinking electrical discharge machining. After investigating the electrochemical machining behavior of copper, suitable parameters are defined for this wear-free working process. In the succeeding electrical discharge machining three consecutive structuring steps are performed using a new tool electrode each time. Reproducing four complex structures and estimating a validation factor for the reproducibility, it is shown that the introduced sequence can be used for machining complex shapes on hard metal.