Re: [CAD_CAM_EDM_DRO] Re: Wire EDM

I have an old copy of a 250 page monograph on ECM.

Tool materials are called out as copper, brass, bronze , stainless
steel, a copper - tungsten alloy for close gaping , and 12% Chromium
steel. For deep hole production-- titanium. no graphite use is
mentioned.

Current densities are quit high-- about 1000 Amps per square inch.
To remove heat flow velocities of the electrolyte may range
from 50 to 100 feet per second.. In practice 100fps is more
normal. pressures are quite high ( Maybe 500 psi) and the force
between tool and work is about the same as in conventional machining.

These indicate that a home built machine is probably impractical.

I know people have done home electroetching for thin part production
( stencils etc) but this not to the same detail and extent as
produced by true ECM.

jesse



People have

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Thomas J Powderly
<tomp-tag@...> wrote:

> Can graphite be used as the electrode in ECM? ( it conducts right? )
> I ask becasue creating graphite tools is easier than creating copper
> tools.

As far as I know it could be used, like you say it is conductive so
the process will occur, it doesn't rust either so would seem OK at
first glance. One thing that might be an issue is the flushing
pressures, they are higher than for EDM I think (not sure) but it
would depend very much on what is being machined.

Of course there is no reason why brass or aluminium could not be used
either, both of which are easier to machine than copper. As far as I
am aware the electrode material has no bearing on the process, some
materials may take some plating more than others I'm not sure.
General corrosion is another issue.

Graham






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