Re: [CAD_CAM_EDM_DRO] Help: PCB Trace Milling Software

Alan Marconett KM6VV wrote:

> Jon,
>
> Thanks for the run down. As I sort of expected, the information is
> not
> in a readily useable format. That's why one of my ideas was to start
> from a HPGL file.

No, this is even worse! At least with the Gerber file, there is only
one line drawn
for every trace segment, and one pad flashed for every pad (although
sometimes,
certain pads are drawn, too, but rarely on raster photoplotters).

With the HPGL, wide traces are drawn by multiple adjacent passes of the
pen, and
all pads are drawn with either vectors and/or circles. This will be
MUCH more
confusing to decipher!

> I think the PCB plot file I was looking at had the
> pen lines at some finite granularity, i.e., something like being on .3
>
> mm spacing (grid), related to the pen width. SO, if it routinely took
>
> some small number of pen strokes to make up a "trace", then these
> could
> be "assembled", and their perimeter could be described as a simple
> contour (for SIMPLE PCB's, the type one might layout with express
> PCB).
> Pads and other shapes could similarly be "built up" to yield a
> contour.
> Once traces/pads have been reduced to simple contours, Vector CAD/CAM
> could generate tool paths for me. And, given that the spacing is
> always
> adequate, as you brought up, it could work.

I think you will find it is a LOT harder to create a general program to
do this for
most cases than it would be to do for a Gerber file, which is already
hard enough!

Jon