Re: [CAD_CAM_EDM_DRO] Re: Software for wire EDM control?

On Wed, 30 Jul 2003, Alan Marconett KM6VV wrote:

> Hi Peter,
>
> I can see that, but if the side of the hull is curved, then I'm guessing
> MANY contours would have to be done, each with a different "slope" to
> the wire, such that it's tangent to a desired contour (watermark?).

Yes, that's what I meant. Also the hull must be convex or it can't be
done. I have no experience with EDM but some with probes/sensors which
must go through similar motions to explore an inside surface.

> The complexity would be in the CAD/CAM drawing. You're right, the Gcode
> remains simple!

The drawing is simple afaik. It's a normal 3D drawing that is reduced to a
triangle mesh or geodetic slice stack and then a program computes the
projected path of a line tangent to the part on two surfaces above and
below the part. I have never done this so I'm talking in third person here
! I also know that there are limits to the angle the wire can take at any
time. This depends on the machine. It limits the angles inside the part to
a small range. Probably less then 30 degrees from vertical in each plane
(assuming the wire is vertical).

Interesting, this answers some of my own questions on how to make a
strange-profiled inside hole in a foam block ;-) Until now I thought I'd
have to make a negative mold but now I have other ideas ...

Peter