Re: EDM

In my reading, the whole idea of electrical discharge is that the
electrical discharge turns the metal to be removed into a plasma. I
am not sure (yet) what happens as the part is turned into plasma, if
the metal expands and that is what 'pushes' it from the cut. or if
the elecrtrolite somehow helps the metal removal.

Personally, I think the electrolite is there to keep the part cool
and help to eleminate any stray arcs from forming.

if that is the case, then atsmospheric pressure will have little to
do with either the operation of the discharge or the rate of metal
removal.

A lower pressure would actually be less effective as any liquid would
boil away and not stay on the part.

Also, if distilled or deionized water was the fluid, simple
evaporation would eleminate the bulk and the residue would not be
hazardous waste.

as a side note, in my searching the issue, I have found a barren land
when it comes to information on EDM's. there is one yahoo group that
is expressly dedicated to edm. had a post last month and one in
september too ! I think about 30 posts in the last 2 years.

There appear to be three books for home brew. Actully 2, the village
press that has 2 versions and are actually compilations of HSM
articles I think, and one on e-bay.

I am guessing that when EDM is all the rage, we will be looking at
ultra sonic metal removal. or is it ultra high frequency impact ?

Dave

--- In CAD_CAM_EDM_DRO@yahoogroups.com, JanRwl@A... wrote:
> In a message dated 12/13/2002 2:18:19 AM Central Standard Time,
> elson@p... writes:
>
>
> > My question: Would there be any good benefit if the EDM work-
> > >electrode system were placed in a lowered pressure environment?
>
> Same topic: I never DID any EDM work, so really don't have much of
a "feel"
> for this detail of which you speak, but the "bubbling and
explosions" at the
> "cut", seems to me, would be considerably altered by a considerable
> "atmospheric" pressure-change where the EDM-vessel was being used.
It seems
> that said "boiling" would be considerably-reduced (tinier bubbles,
or none!)
> if the process were done under TWO or more atmospheres of ambient
pressure!
> Note the "black smoker vents" at the bottom of the ocean in those
PBS
> educational shows: There is NO "steam", yet the temperature of the
water
> directly IN those jets is 1400°, as that is many hundreds of feet
below the
> surface of the sea! So, EDM done under high pressure migh, say,
result in a
> VERY smooth (polished?) "cut-surface"? Some one "in here" into
experimenting
> oughta TRY this! I see a potential market for "containment
vessels" for
> EDM'ers, etc... Hmmm...
>
> Jan R.
>
>
> [Non-text portions of this message have been removed]