Specs for EDM power supply

[galaxy]

I want to build an EDM power supply, therefore i need some specs to come to a good design.
So the following questions arises:

AC, DC, or PWM ?
Frequentie ?
Volts ?
AMPs ?
Anything else ?

It is intended for light-duty EDM. Let's say PCBs

I am able to design a processor controlled power supply.

I am willing to publish the schematic on this forum, after i have succeeded.

Thanks in advance for your replies.

Theo

[Mat-C]

From my research (currently building my own WEDM, so not actually tested)

AC: pretty advanced, used to avoid surface electrolysis, esp. for titanium.
DC: Do you mean capacitor discharge? Easy/works/slow.
PWM: Standard "DC" methord, should be reasonably simple to make.

Volts: Commercial machines seem to use 27 to 250v. Bigger voltage = easier life (larger gap) but more dangerous. Seriously, be careful.

Amps: Try it and see... more amps = faster cutting, but speed isn't your first problem.

PCB's: you also need to control the z height fairly accurately I'd think. What do you plan to use for a probe?

Are you upgrading an existing machine or starting from scratch?

[galaxy]

To start with your last question, i'm starting from scratch.
I intended to make a pcb milling machine. Lucky enough i stumbled over EDM before i actually made the Z-axis.

Power supply: Maybe the best solution is to make a PWM-contolled one in the whole voltage range you mentioned.
I have a 4 AMP variac at home. Maybe that is a good starting point.

I found on the web a dedicated forum about DIY EMD.
For me, it is the place to be...

http://tech.groups.yahoo.com/group/EDMHomeBuilders/

Thanks for your reply.

Theo

[Mat-C]

4amp variac should do it. Be careful with those voltages! Use an RCD on the mains side and have an audible and visible warning of the wire being possibly live.