Homebrew PCBs

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@...> 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
>