With photo sensitive boards, I have found that drilling before
developing/etching tears away a bit of the photo-sensitive coating,
causing copper to be etched away from the hole (not a good thing). A
friend of mine that uses PNPBlue (toner transfer) says when he tried,
the little burrs kept the toner transfer paper from making good
contact around the hole. But I bet with a _good_, high speed spindle
and real PCB carbide drill bits, it might work out O.K. Heck, pro
shops do it without problem... but then again, their spindles cost
orders of magnitude more than what I have (www.CNCOnABudget.com, $100
or so).
- Steven Ciciora
--- In
Homebrew_PCBs@yahoogroups.com, Stefan Trethan
<stefan_trethan@g...> wrote:
> On Fri, 09 Jan 2004 02:08:13 -0000, dkesterline <desterline@t...> wrote:
>
> > I'm in the proccess of setting up a CNC drill, the thing I'm
concerned
> > about is getting the etched board on the drill tblw acuratly.
Seems it
> > would be easier to align the TT to the holes.
> >
> > Agreed about using the etched board for aligning the drill. That's
what I
> > do when it's by hand, I'm just tired of doing it by hand :-)
> >
> > -Denny
>
> sorry, i assumed hand drilling.
>
> with cnc it may be much easier the other ways.
>
> take two steel pins (broken hss drill bit shafts or so, thin nails)
> and put them in the holes (snug fit that they are straight.).
> punch the same two holes through in the tt paper (drill, needle, etc).
> (maybe best using far apart pins for this).
>
> then put the paper on the pcb, the pins will align the paper.
> with the tip of your iron now heat between the pins, to stick the
paper to
> the pcb.
>
> remove the pins and heat like usual.
>
> maybe that works?
>
> Stefan