Re: ECM, The poor man's EDM??

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "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

Op's I had assumed a unitary electrod on the end, not one that would
be intermitant.

If it were unitary, then the time of etching would be constant,
whereas a small say, 10% section on the side, would etch at a much
slower rate.

I guess as more people try this type of machine, these problems will
be solved.

Another not about rotating, if you use an tube type electrode and have
a wire across the end, there will be no stub left as the unit will cut
it out. This will take longer of course, but the wire would allow
flushing.

OK, another though... the wire as the electrode, from side wall to
side wall (both end and center cutting) would cut what could be
claculated out to be concentric circles only atoms wide. then the
diameter of any part of the wire can be calculated. the very center
would have a very small circle, so the electrode hang time or cutting
time would be a very high percentage. the perimiter of the electrode
would have a much larger concentric circle and therefore a much
shorter hang time.

Very interesting stuff.

Dave

>
>
> >
> > 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
> >