If you read all my posts you would see that I've done all that except
the etching . Threads are so difficult to follow in these groups. Why
etch when you can just use the artwork on paper and tape it to a
piece of board. Don't waste time etching anything during the
calibration phase.
--- In Homebrew_PCBs@yahoogroups.com, David McNab <david@r...> wrote:
> Don't know if it's a known problem, but something you could try is
to:
> - print out a test pattern
> - etch it to a pcb
> - program it to your cnc rig.
>
> Then:
> - stick a scriber bit into the cnc rig
> - start the drilling run
> - measure the errors in both directions
> - convert these errors to x and y percentages
>
> With this info, you'll have two different options:
> 1) transform the artwork prior to printing, so it
> matches the CNC
> 2) transform the values in the drill file, prior to
> submitting it to the CNC rig, so the drilling
> matches the artwork.
>
> Given that I'm comfortable with python scripting, I'd go for option
1,
> and write a python/PIL script to transform the artwork.
>
>
> derekhawkins wrote:
> > Hi,
> >
> > Just finished putting together a CNC drilling machine and have
now
> > stumbled on a problem that I never anticipated....The drilling
machine
> > appears to be more accurate than the printer used for the PCB
> > artwork....Tried both a HP2420 (laser) and Epson 2200 (Inkjet)
and the
> > results were similar. Is this a known issue with CNC setups?
> >
> >
> >
> >
> >
> >
> >
> >
> > Be sure to visit the group home and check for new Links, Files,
and Photos:
> > http://groups.yahoo.com/group/Homebrew_PCBs
> >
> > If Files or Photos are running short of space, post them here:
> > http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> >
> >
>
> --
> Cheers
> David