Re: Software for wire EDM control?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Alan Marconett KM6VV
<KM6VV@a...> wrote:

> It sounds like EDM is also done with a wire, like cutting foam

wings?

Yes the taper (or not) is programmed in as a difference in the linear
axis locations between the top and bottom set of wire guides. In 4
axis Wire edm the part is always stationary as the taper is not
accomplished by tilting the part.

Some machines (Agie) are programmed as R-theta, polar coordinates.
Some simple machines use an angle setting and 2 axis coordinates.
These usually are not useful for any complex shapes like a circle to
a square transition. Common uses for the simple angular style are
punch press Die and punch clearance cutting. These shapes are defined
as a 2D contour with a draft angle all the way around (some have a
straight section along the wall too) Another example would be the
manufacture of simple Aluminum or plastic extrusion dies. Complex
shapes usually require full 4 axis programming, as the entry and exit
holes on an extrusion die may differ considerably more than just an
angle off the exit hole.

> Sounds like there is more to it then just "wiggling a little wire
> around". And they do this X-Y U-V in a tank of water? ;>)

The process is usually flood-flush today, not submerge. Also the
wire is not fixed like in hotwire plastic cutting. It traverses at a
precise rate across pulleys on either side of the guide eyelets.
this helps with particle removal and the size of the cut does not
change due to erosion of the wire. It is not unusual to have .0001-
.0002 inch depth finish passes to make a precision flat surface (just
a skim cut with no programmed move too). Also the internal corners
are radiused at the same size as the wire. About .005 in or so.
Just about as good as you can get with a broach, without the custom
tooling for each part.

Fred Smith - IMService