Sinker EDM capacitor box box use?

Just acquired a XLO sinker EDM, it's a basic machine and there is a capacitor accessory box hanging on the tank. If anyone is using one please explain when it would be useful in burning. There are several settings from one to .001 to 10 MFD and two easily connected wires with alligator clips.
Thanks
Dixon

Hi Dixon:
On these older manual sinkers, the spark gap conditions have to be set manually in order to get the proper balance between spark energy, spark frequency, and spark duration.
The settings you choose depend on how big the surface area of your electrode is, how fast you hope to burn, how much electrode wear you can tolerate, and what surface finish you hope to achieve.
The capacitor box allows you to switch a range of capacitor values into the spark generating circuit, and the capacitance acts a bit like a dam or a valve; allowing the spark energy to build up to a higher threshold before it lets go and blasts a bit of the workpiece away.
The result is faster cutting, but at the expense of increased electrode wear and a rougher surface finish.

When you don't care how much wear you have; say you're burning out a broken tap with a simple tube electrode; that's when you can pour the coals to it and use the capacitor box.
When you are burning a mold cavity with a complex electrode that took hours to make, that's when you set your priorities differently and accept slower burns to preserve the expensive electrode.

That's it in a nutshell (the simple version).
Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

Thanks Marcus, I'll try it out soon on a test piece. BTW, there are only two leads, one red, one black, does it make a difference which way it is wired? There is no actual power input, so I suspect the unit gets all its power from the EDM power supply itself, right?

Hi again Bluechipx:
I've never actually used an Excello EDM machine but I expect you'd set the capacitor box leads according to the polarity you chose for the electrode.
Since it's a DC circuit you may pick the current flow direction either electrode positive or electrode negative.
I assume but do not know that you'd wire the capacitor box in so the current flow direction matches.
The oldest machines I've run had this capability hard wired into the control and it would switch automatically.

Cheers

Marcus