Re: Die sinking power supply for Wire EDM

Great reply. This is great information
Thanks

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Marcus" <implmex@a...> wrote:
> Hi kdoney:
> Theoretically, you should be able to make the adaptation, but
there are
> likely a lot of details that will be a challenge for you.
> First, the sinker power supply typically puts a lot of current into
the
> electrode, compared to a wire power supply.
> A sinker trode usually has the mass to handle it, whereas a wire
can't take
> much.
> So the power supply is set up in the wrong amperage range...should
be
> fixable.
> Second, the sinker senses voltage agross the spark gap and directs
advance
> or retreat of the electrode via Moog valve and hydraulic cylinder,
or
> stepper/servomotor and screw.
> That sensing circuit has to be adapted into the wire path.
> Third, typically sinkers use oil dielectric whereas wires use
deionized
> water...the dielectric constants of these two media are likely
different
> enough that you need to tune the sinker control to get useable
performance
> in the wire environment, unless you stay with an oil dielectric
(very slow).
> Fourth, wire power supplies are pretty sophisticated in how they
respond to
> fast changes in the spark gap voltage.
> They continuously diddle the voltage, frequency, amperage, off and
on times,
> rate of advance & retreat etc, etc.
> They require this sensitivity because of the difficulty of
maintaining
> constant dielectric conditions in the spark gap zone.
> A sinker power supply from an obsolete machine is not set up to do
> this...you may have insurmountable difficulties maintaining a
stable spark
> gap just because the supply can't respond fast enough and in enough
ways.
> That translates into more ramming events and more arcing events,
both of
> which break wires.
> So...it's probably doable if you've got the knowledge to poke
around in the
> electronics, but you ain't gonna get commercial wire cutting
speeds, and
> you'll likely be severely limited in the thickness of material you
can cut.
> Expect also to use a LOT more wire per cubic inches of cut than a
commercial
> machine, and expect more wire breaks.
> Having said all that, a transistorized sinker power supply is a
helluva lot
> better than a home cooked capacitor discharge supply, so you may
find a
> workable solution that is better than the unaltered plans call for.
> I commend your effort...keep us posted
> Cheers
>
> Marcus
>
> ----- Original Message -----
> From: kdoney_63021 <kdoney_63021@y...>
> To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> Sent: Saturday, November 15, 2003 3:48 AM
> Subject: [CAD_CAM_EDM_DRO] Die sinking power supply for Wire EDM
>
>
> > I just bought a Charmilles D10 with a good power supply and was
> > wondering if I could use the same supply on the WEDM I am building
> > from Dan Mauch's plans. I haven't gotten my schematics or user
> > manuals yet so I don't know all of the specifics.
> >
> >
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