Re: [CAD_CAM_EDM_DRO] Re: ECM, The poor man's EDM??

Graham,

How about a delrin rod with flutes on the side to allow the coolant back out
with a wire thru the middle?

Just a thought.

George

----- Original Message -----
From: "Graham Stabler" <eexgs@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Monday, September 19, 2005 11:32 AM
Subject: [CAD_CAM_EDM_DRO] Re: ECM, The poor man's EDM??


> I am trying to do ECM, in EDM they use a tubular copper electrode
> with internal flutes, they then spin it, this means the workpiece
> sees a solid electrode even though the dielectric is being flushed
> through it. In ECM it is a little different, especially in my
> gravity feed version. I am trying to use insulating parts on the
> electrode to set the gap while still allowing ECM action. I suppose
> this could alsow be done in EDM however and it is a big however.
> The electrode in EDM is also eroded so whatever clever trick you did
> would have to adapt with the constantly shortening electrode. In
> ECM the electrode does not degrade.
>
> I even tried wire ECM of sorts with a stiff wire electrode and some
> glass fibre braid (allows electrolyte and current through but does
> not allow short circuit), it does work however I thing I was getting
> arcing as eventually the braid would get holes in it. This might be
> corrected with better filtering of the electrolyte.
>
> A good ECM link:
>
> http://electrochem.cwru.edu/ed/encycl/art-m03-machining.htm
>
> please have a read everyone, this could be very cool.
>
> Am now thinking a simple current monitoring z-axis maybe the way
> forward.
>
> Graham
>
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, R Rogers <rogersmach@y...>
> wrote:
> > Graham, I was at a tool show the other day and they had an EDM
> type machine that did exactly what you are describing. Not sure what
> they are using for an electrode. It looked like a brass rod. I
> talked to them breifly and the machine was for starter holes. It was
> only $20k..:-)
> >
> > Ron
> >
> > Graham Stabler <eexgs@n...> wrote:
> >
> > You can use a rotating electrode where the insulator extends
> beyond
> > the conductor but only intermitantly, that way as it rotates the
> > workpiece sees the electrode for half of the time (say).
> >
> > The supply needed is just a DC supply, for what I was doing
> something
> > along the lines of 40v 5A is fine.
> >
> > Graham
> >
> >
> > >
> > > If I can envision what you are saying, the insulation prevents
> the
> > > hole from being larger than the electrode, that is until the
> bottom
> > is
> > > cut deep enough that the sides start to be eroded.
> > >
> > > What about a rotating electrode, with one point that is a
> conductor.
> > > 90% of the cut would be down, 10% sideways.
> > >
> > > Easier than EDM ? what type of power are you using ?
> > >
> > > Dave
> > >
> >
> >
> >
> >
> >
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>
> OFF Topic POSTS: General Machining
> If you wish to post on unlimited OT subjects goto:
aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if
you have trouble.
> http://www.metalworking.com/news_servers.html
>
> http://groups.yahoo.com/group/jobshophomeshop I consider this to be a
sister site to the CCED group, as many of the same members are there, for OT
subjects, that are not allowed on the CCED list.
>
> NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM.
DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
> bill
> List Mom
> List Owner
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>
> Yahoo! Groups Links
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