To get a continuous arc the electrode or wire has to keep the right distance to the workpiece at any time. For keeping the arc at the right distance I wrote some code for the Marlin Firmware that measures a voltage provided by a current sensor to move the electrode towards the target position as long as the current is lower than a defined value. If the electrode touches the workpiece the current increases above the defined value and the electrode stops and moves back to where it came from until the current is again below the defined value. This gets repeated continuously until the electrode reaches the target. The electrode does that very fast at a low feedrate, so that it does not move a large distance in every direction and so it keeps the right distance at any time what leads to a stable arc.

Here is the code that I wrote:

https://github.com/DerM4209/Marlin_ECM_EDM_Mode

If you are good at coding and want to integrate this feature into the Marlin Firmware, it would be nice if you could help me to clean up the code, to make that possible:

https://github.com/MarlinFirmware/Marlin/issues/22849

I think with the infos about the water system, electronics and the closed loop control you should be able to build your own sinker or drill EDM machine.

Because I want to use EDM as a more silent and more precise alternative to plasma cutting and CNC milling, I need to upgrade the machine so that it is able to cut out workpieces. The current problem with that is the wear of the electrode and so I need continuous refreshing of it, for what I will need a wire EDM system.

There are some good Wire EDM designs out there and I will try to build something like that by myself in the next days and weeks.

I will keep you updated....