At 10:33 AM 8/2/02 -0400, you wrote:
>What is an electric erosion machine?

Probably a spark erosion machine, usually called an EDM (electrical
discharge machining) machine (sorry for the redundancy).

They have an anode machined to the negative image of the shape you
want to create that is moved within sparking distance of the
part to be machined. Tiny sparks through a dielectric fluid remove
material which is carried away by the flowing dielectric. They
are really common in plastic mold (or mould) and die manufacturing,
because the electrode is often much easier to machine than the opposite
shape (imagine trying to make a perfect triangular hole with sharp
corners in a  piece of half-hard tool steel, compared to just milling
the 3 sides off with a nice carbide cutter.

There are also wire-cut machines that use the same principle, but
with a brass wire. They cut through materials, hardened or not,
like a fine bandsaw. Want a piece of stainless 4" square and 1"
thick cut to the outline of a map of the CONUS?  Easy. The wire
is slowly fed through tensioners because the wire iteself erodes
away as the machine runs. These are common in making punch and
extrusion dies. The machines can generally cut perpendicular to
the material or move top and bottom tensioners to make an angled
cut. There's even a fellow in the Windsor ON area (member of the
Detroit metalworking club) who has made one from scratch himself.
Mr. Robert Langlois, if I got the spelling right.

Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
9/11 United we Stand

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