The generator should be set accordingly. of nonconducting ceramic ZrO2 The electrode wear can be noticeably reduced by introducing tool rotation; however, with values of ≈ 75% relative wear there is still a high reduction potential.
Fig. 14. Tool feed (s) during uEDM of nonconducting ZrO ceramics (tool ุ120 ตm)
Fig. 15. Cross section of uEDM bores in ZrO2 ceramic, diameter 200 ตm, tool ุ 120 ตm
Pulse analysis shows a change in the discharge shape from machining the starting layer, where short pulses similar to discharges in metal approximately 2100 ns long are observed, to machining the base material.
There, the discharge shape changes to a short peak followed by a long hold period at low currents.
This type of discharge can last up to 8 us and its second part is expected to be the period where the carbon layer is deposited.