Hi Alan,
I built a similar unit for receiving Radio Faxes
from around the world VIA a shortwave radio. My unit used
stepping motors from a floppy. That's 20 years ago! Here
is a picture of the unit. I used some of Ralph Taggerts
circuits and some of my own. I went on to design a circuit
board that goes in the computer. I used FAX_Dhals.
see machine at:
http://crankorgan.com/kleinfax.JPG 73s
John
--- In Homebrew_PCBs@y..., Alan Marconett KM6VV <KM6VV@a...> wrote:
> Hi Steve, John, list,
>
> check out Jon E's photo plotter:
>
> http://www.artsci.wustl.edu/~jmelson/photoplot.html
>
> While it plots to film, I think you can get a few ideas from it.
And
> there are advantages if you can generate a good film, such as
exposing
> as many boards as you want from it.
>
> But yes, I DO like the concept of mechanical etching! And the
software
> to do the isolation tool paths is very interesting to me
(programmer).
> As well as the controller it's self!
>
> I don't know the linear speed of Jon's photo plotter (perhaps it's
that
> the film is faster then the photo resist), but I'm surprised it
couldn't
> be made to work. A laser out of an HP laser printer? Then you'd
need a
> mirror to get the light over to the "pen lens" and down to the
board.
> Put the hole laser thing on the XY carriage? Yeah, that could work!
>
> Perhaps we'll get a little more info on the HP, and someone can try
some
> experiments on exposing the resist on a board with a laser! And who
> cares if it takes a long time? Controlling the size of the
laser "dot"
> on the board with an aperture would be the tough part. I'm told
that
> commercial photo plotters use an aperture disk, which is a set of
> "films" with an appropriate mask.
>
>
> Alan KM6VV
>
>
> Steve Greenfield wrote:
> >
> > Yep, far too long to expose, and the problem of "blooming". UV
> > laser, anyone?
> >
> > That sounds do-able! It would just require modifying a pen with
one
> > of those carbide point marking pens. I think you could probably
> > just spray something like one coat of black fast drying laquer to
> > scratch through.
> >
> > And one of the things I've always liked doing to boards I make is
> > sign them. Couldn't do that when I made some with the vinyl
cutter.
> >
> > So the only issues are paint that will scratch away cleanly and
> > that it leaves a wide enough opening after etching.
> >
> > Steve Greenfield
> >
> > --- crankorgan <john@k...> wrote:
> > > Hi,
> > > Nobody liked my light on a plotter idea. I was told the
> > > light source would have to move too slow. The board would take
> > > way to long. Ok, I use Mechanical Etching bits myself. But what
> > > if you coated the whole board with resist. Then you put a sharp
> > > point in the plotter. Have the plotter do isolation paths. Then
> > > the board goes to the acid.
> > >
> > > John
> >