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

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Graham Stabler" <eexgs@n...>
wrote:

> 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

The concept is similar to electroplating, but what surprizes me is
that there is no build up on the cathode.

I was actually hoping that build up would occure so I could use the
principal as a means of filtering the water from my EDM.

Dave