RE: [CAD_CAM_EDM_DRO] STEPSTER: how many use it and are you aware of any particular problems

HI Daniel,

Ambitious undertaking!

If you don't mind Pascal, I'd look at TurboCNC. Minimal contribution needed
for source access, well worth it.

Stepster is no longer supported to my knowledge, TurboCNC has a
development/support team.

Controllers that process Gcode don't normally process Gerber or Excellon
files, at least not hobby programs.

Are you really going to move an aperture, and expose film? Or do you just
want to extract the paths?

I added limited capability to my STEP4 CNC controller program to read Gerber
files, and generate Gcode. A tough job! And I'm limited on how big a board
I can handle. Are you reading RS-274D (hope I have that right)? Then
you'll also have to use the aperture data to build a "pad table" of some
sort. Gerber files are also "scaled", i.e., no decimal points are used. So
the values might be 1020 for a 10.20" coordinate with a particular scale.

There is also a header that tells (on RS-274D?) what the scale is, board
size and a few other things I forget.

Assuming you are generating ISOLATION traces (big assumption!), then you'll
need to transverse the Gerber data, and build a b-tree or similar structure
to hold nodes. The nodes would be the pads, vias or endpoints of your
traces. Each node would have the pad size, maybe hole size (mind didn't),
and pointers to the parent and children (traces to other pads). You'll also
want the trace sizes (apertures) in this node.

Once you have the tree built (an array), then you can discover the entry
points for all of the nets.

To generate Gcode for a trace (actually, I just generated PLC code to import
into Vector CAD/CAM) you just "walk" each net going around one side of all
the traces and pads. You will arrive back at the start of the net. You'll
want to add an offset to the Gerber path as you go around a net, such that
1/2 the trace width and the radius of each pad you encounter is
accommodated. Don't forget, you can have round or square pads, and
intersections, and angled traces, and ....

Go through all the nets, and the PLC (point, line, circle) or Gcode you
directly generate describes the board.

The Excellon file I think, is just a list of holes and sizes, with the
coordinates for them. Not hard to generate a Gcode file from them, or do a
simple conversion to PLC and import them into Vector CAD/CAM.

With the PLC imported into Vector, Any fixes can be done, and then you can
let Vector generate the Gcode. Each net generates a tool down, a transverse
of the net (go around the net and come back to the start), and then tool up.


You'll want to arrange the start of each net in the most efficient order
(traveling salesman algorithm), of course!

I found it an interesting project! I wish you luck on yours!

Alan KM6VV

> -----Original Message-----
> From: CAD_CAM_EDM_DRO@yahoogroups.com
> [mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of D. Daniel McGlothin
> Sent: Tuesday, July 19, 2005 8:36 AM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: [CAD_CAM_EDM_DRO] STEPSTER: how many use it and are you aware of
> any particular problems
>
> Hi,
>
> I'm interested in how many people might be using Kevin Carroll's STEPSTER
> (or SUPER STEPPER).
>
> I'm also interested in actual user's impressions of any particular
> shortcomings or problem areas experienced with STEPSTER.
>
> I am not particularly interested in comparisons to other CNC software
> packages, although if you are aware of free, open sourced software (other
> than EMC) you might mention that.
>
> The purpose for these questions is as follows: I'm considering using
> STEPSTER code as a basis of an embedded 3-axis stepper controller whose
> programming interface is G-Codes sufficient to process Gerber and Excellon
> files. Before I would embark on this project, I thought I'd see if there
> were any operational problems I should be aware of that might be "fixable"
> in the porting of the code.
>
> Daniel
>