Hi William:
Some things about discharge dressing:
First, you need to set the cutting conditions for maximum wear on the electrode so when you drive your dressing block past the trode it will preferentially burn the trode rather than the dressing block.
Second, you want your electrode to be burnable ie, not too wear resistant.
Both of these things are exactly opposite to what you normally want in your electrode, so it seems a bit counter intuitive until you think about it as the electrode becoming the workpiece temporarily while the discharge dressing takes place.
So normally, the trodes are copper or Telco and the dressing block is copper tungsten or tungsten or tungsten carbide or even graphite.
You give up wear resistance in the trode to get the ability to discharge dress it, and you accept that you will have to re-dress the trodes a lot.
Also, you need a means to rotate the trodes if the gates are round, so either a C axis on the ram, or a Rotobore.
The method is to drive the dressing block past the trode so the trode is eroded to the proper shape by the profile you've put onto the dressing block.
The details of how to do it on your machine are what you have to figure out.
I've had best success taking a NO-WEAR setting for copper vs carbide and just reversing the polarity; whatever those settings are they should give you a good start point.
Having said all that, I've had better luck overall with pre-made trodes than discharge dressed trodes for round features in super small diameters.
I've been successful with pure tungsten wire, with tungsten carbide with copper tungsten and with POCO Angstrofine graphite, depending on what I was trying to do.
My current favourite is pure tungsten if I can buy wire in the proper diameter.
I have a range of tiny home built collets for clamping and centering the wire and I find I get best, most trouble free performance that way.
Often the secret to success is the have the wire a bit eccentric to the axis of the rotary; that way there's room for dielectric to get down the developing bore a bit better
A thou or so of runout is all it takes.
That's it in a nutshell; it's not very complicated to do with no real super sophisticated programming to do either.
Cheers
Marcus
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