Homebrew PCBs

Hi Alan,
        If you do a circle in GCode it has four lines of code. If
you use Eagle each circle becomes alot of points. The resulting
code for a large PCBoard is huge. I look to produce a fast efficent 
GCode file. One of my DXF files is in the Files section. After I 
convert a DXF to Gcode I go in and do some touchup. With a large file 
changing all the Z-002.45 to Z-002.46 takes for ever. I use an old 
version of KCam that was FREEWARE. It has problems with large files.
    Simple circuit boards with only one or two IC mask the problems 
that show up on large boards. Learning a few tricks now will pay off 
later.
      When you draw in DXF, you can have traces share a border. This 
cuts cutting time and wear on the tool. My large circuit boards have 
500 inches of cutting distance. The new board I just designed has 600 
inches of cutting. Simple hobby circuits might have 50 inches. This 
is why you will see people reporting success with different cutting 
tools. For large boards you need Carbide or Diamond.
      When your machine cuts a board how much extra traveling are you 
getting. That's where the machine cuts here, then there, then over 
there. The ACE converter takes the unwanted moves out. I don't use 
ACE myself. I have found that the GCode will turn out just the way 
the DXF is drawn.  So I draw the DXF, then I trace it in a nice 
orderly manor. I save the trace! The results is the machine cuts
moves a little and it cuts again. 
      As for your OT question. I was told I should have gone for a 
Goverment grant.

                                     John       
        



--- In Homebrew_PCBs@y..., Alan Marconett KM6VV <KM6VV@a...> wrote:
> Hi John,
> 
> Not sure why you say it takes lots of lines of code to do round 
pads! 
> Although I'm working from a Gerber file (thinks pads and traces), 
the
> resultant actions to draw a round pad are actually quite simple (I 
don't
> generate an intermediate Gcode file... yet).  There are from 1 to 4 
arcs
> (for 0 to 4 traces into pad), plus a line per side of each trace, 
up to
> the next pad, or a "bend" in the trace.  So a simple "dog bone" of 
two
> pads and a trace between would result in two arcs, and two traces!  
And
> if I understand you correctly, you'd draw 7 short lines per pad, 
plus
> two traces?  
> 
> This actually gives me an idea.  If the "short lines" used to draw 
the
> pads could be identified by software (a "filter" based on length?), 
then
> they could be replaced by arc's.  sort of like a "constant 
contouring"
> algorithm.  Then you'd get round pads!  
> 
> OR, since you're using CAD, and you always start/stop the little 
line
> segments always start on 45 deg. points of a circle (I guessing 
here),
> I'd suggest just specifying a arc from/to the required points at 
each
> pad!  That should be simple enough!  
> 
> Of course all this assumes you would want round pads instead of
> octagonal pads.  What are your thoughts?  I know you've done many 
boards
> with your "system", and you have your reasons!
> 
> Alan  KM6VV
> P.S. Hate to mention it, and I don't know your tax setup, but 
just "not
> making money" isn't enough to make you "non profit".  As far as I 
know
> (I'm not a tax consultant), just selling services/products makes 
you a
> business (you just report little or no income from the business on 
your
> schedule C).  Just some thoughts, and hope this didn't offend.  :>)
> 
> 
> crankorgan wrote:
> > <SNIP>
> >   Dave is using round pads. They look nice but the cause
> > lots of lines of code. This can come back to bite you if
> > you have to rework the code. Almost one hundred lines of code for
> > each pad. I use an eight sided pad. Daves machine is very tight
> > with the use of the antibacklash nut-spindle and machined guides.
> > 
> >                                         John