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.