[Pcb2gcode-devel] Fw: Re: pcb2gcode oddities

[Patrick B. <pbi...@us...>]

On Tue, 26 Jul 2011 22:35:31 -0600
John Bump <joh...@gm...> wrote:

> I'm not calling these bugs because the program works, but they might help
> other people who are running into the same problems I ran into and they
> might be things the developers might want to change.  I'm running pcb2gcode
> 1.1.2 on ubuntu 11.04
> 
> 1.  If there's a millproject in the directory, pcb2gcode seems to use it,
> even if it's not asked to.  If I run pcb2gcode --front="front.gbr" [lots of
> options] and I have a millproject around that contains an
> "outline=outline.gbr" line, I get an outline.ngc as well as front.ngc -- and
> in that case it's obvious what's happening, but if the only difference is
> something like offset=0.003 when millproject has an offset=0.010, that's
> more difficult to track down.

The idea was:
* parameter values can be set via arguments on the command line, or placed
  in a config file called "millproject" to save typing
* command line parameters override stuff set in the config file, so you can
  for example run "pcb2gcode --offset=0.05" to quickly try a different offset

This is, however, undocumented.
If you think you have a better idea, shoot! I'll be glad to put it on my
TODO list if it's an improvement.

> 2.  When I run, let's say, "pcb2gcode --front "driver.front.gbr"
> --cutter-diameter 0.004 --zcut 0.007 --cut-feed 10 --cut-speed 20000
> --cut-infeed 0.007 --zsafe 0.025 --mill-speed 20000 --mill-feed 10 --offset
> 0.004 --zchange 2.00 --zwork 0.004" I get a good front.ngc output, with a
> good toolpath.
> If I then run " "pcb2gcode --front "driver.front.gbr" --cutter-diameter
> 0.004 --zcut 0.007 --cut-feed 10 --cut-speed 20000 --cut-infeed 0.007
> --zsafe 0.025 --mill-speed 20000 --mill-feed 10 --offset 0.004 --zchange
> 2.00 --zwork 0.004 --outline "driver.outline.gbr" -- just adding the one
> extra parameter that has it process a second file -- the front.ngc is
> essentially blank.  It has a 5-item preamble, issues a G64, a G04 P0, a G00
> Z2.0000, an M9, and an M2, and that's it.  The same thing happens when I add
> all the relevant parameters for the outline cutter, or if I have a
> driver.back.gbr that I try to isolate along with the front.
> So if I want to get good front and back isolation files I need to run each
> of them separately, and then run the drill and outline files.
> It works just fine when I do that... but since it can process multiple
> files, and produce outputs, it took me a while to figure out why I was
> getting blank front and back isolation layers, which might be confusing to
> other beginners.
> 
> I've had exactly the same thing happen with any millproject file I've used,
> but I haven't actually tried a millproject that just works on one layer at a
> time.
> 
> Anyway.  When I crank out one layer at a time it works great and the output
> is lovely, and it's awesome to be able to mill my own PCB's, so thank you
> very much for making this piece of software.

pcb2gcode <= 0.4.5 used to process each layer individually like you do, but
it was cumbersome to get the layers to align because it was usually necessary 
to reset the machine's coordinate system and do some calculations by hand.
Since 1.0 or so, pcb2gcode can process all files at once and do that
automatically, so you only have to flip the board once.

The problem you most likely have is that pcb2gcode misinterprets your outline
file.
You can read why this happens, how to fix it and why it's all my fault ;-) here:
https://sourceforge.net/mailarchive/message.php?msg_id=27934225

It's nice to hear you like the output, I'm quite content with it myself ;-)
Ease of use could still be improved though, and there's almost zero
documentation. I've wanted to write a tutorial since last year now, but
there's always been someting more urgent to fix, hope I'll get to it sometime.

Again, if you have any ideas on how to improve the program, please share them.

-- Patrick