RE: [CAD_CAM_EDM_DRO] Re: -- EDM power supply -- two paths

Yep, a pulsed power supply for sinker EDM sounds like a good place
to get started. So, what ins and outs does it need? Something
like this?:

INPUTS:
Power (120VAC)
Enable
Gap voltage setpoint
Pulse width
Pulse frequency

OUTPUTS:
Anode/cathode
Feedhold (to PC)
Reverse (to PC)
Dielectric pump on/off
Fault (to PC) for shorts?

Just wondering: for the RC type circuits already out there with
stepper outputs, do they actually backup the electrode? Or, do
they just feed/hold/feed/etc.?

Regards,

Carlos Guillermo
VERVE Engineering & Design

-----Original Message-----
From: Graham Stabler [mailto:eexgs@...]
Sent: Saturday, July 19, 2003 9:24 AM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] Re: -- EDM power supply -- two paths


I have to aggree that a sinker would make a much easier project to
start with and have much fewer distractions such as the software.
A
pulse circuit would also be a must. There are already some good
plans out there for simple RC units.

What is required is some sort of specification for a PSU, this is
not
just voltage/max current but also controls in and out and the
feedback required within the unit. That way it might be possible
to
create a general purpose PSU that connected to a PC with the
relevant
stepper drivers could form the powerhouse of a wire or sinker
unit.

If you consider the cost of a commercial sinker unit that includes
mill type mechanics, a computer unit and monitor, steppers/servos
and
drivers and the PSU itself you see we have an advantage. Anyone
with
a CNC mill controlled by a PC already has most of these items. So
the cost is really just the PSU and that MAY be quite economic
given
that you can buy PWM chips, mosfet driver chips and Mosfets and
very
good and fast microprocessors with RS232 and god knows what else
all
for small bucks.

I am going to start having a look in the library and in the
various
online patent offices to see what can be gleamed.

Graham



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