Copper vs Graphite EDM
by Len Reiker
(St. Louis, MO)
Which is the best electrode material to use to EDM tool steel? I have been running EDM's for about 12 years now and I use both copper and graphite for my electrodes. Both materials seem to work well, but I tend to use them for specific purposes.
I use copper to make my electrodes when I have a tool to make that I can burn fast. For example, I use copper when I make a female electrode to burn the profile on the outside of a tool, or when I have a deep hole to burn. It seems to last longer and I can burn faster.
I tend to use graphite when I have to burn a fine detail on a tool, like a face detail on a punch or a gear profile. Graphite seems to hold the detail better but I have to burn it slower.
Do you have the same practices? Does anyone have a better way to EDM tool steel?