Homebrew PCBs

like the HP7475a which I own, I've written some code to also use it 
as an XY pen-plotter.

I already own one.  I tried using it before, but didn't like the 
results.  I even modified a couple of pens as I thought this might be 
an easy way to "draw" boards to etch.  I have owned this plotter 
since new a long time ago.....

The main problems I had with trying the plotter were:

1. The ink would not last through the etch.  At the time I think I 
had tried to use a OHT marker (cut it off and used one of the plotter 
pen bodies).

2. When the pen would "land" on the copper, tiny ink droplets would 
splatter and make a mess of the fine traces.

3. The speed seemed WAY too fast to get nice dark lines that you 
could get by hand with the same pen.

4. Securing the board to backing paper.  As the plotter requires 
paper to "grip".  (The paper movement also seemed WAY too fast and 
would sometimes move the board out of registration.)

5. The process seemed slow, and since I never got a decent board to 
etch with this method, I abandoned it.

The plotter now once again collects dust in the closet :(

If you have any ideas to try, or like you said, software to try I 
would be game to try it once again as I would like to get some more 
use out of this practically new plotter.

--- In Homebrew_PCBs@y..., "caveteursus" <j.walton@a...> wrote:
> like the HP7475a which I own, I've written some code to also use it 
> as an XY pen-plotter.

1)You can't use the HP pen's  they aren't waterproof.  Others have 
suggested using modified Staedler waterproof pens.  2) The plotter 
speed can be explicitly controlled in software.  3) Mount the board 
on a mylar overhead transparency film -- this is plenty rigid. 4)the 
original post dealt with repurposing the HP7475a as an XY pen 
plotter.  I wrote some code if anyone cares to take two 0-5V inputs 
and convert them to the XY coordinates.

Jack


--- In Homebrew_PCBs@y..., "johnman9146" <johnman@d...> wrote:
> I already own one.  I tried using it before, but didn't like the 
> results.  I even modified a couple of pens as I thought this might 
be 
> an easy way to "draw" boards to etch.  I have owned this plotter 
> since new a long time ago.....
> 
> The main problems I had with trying the plotter were:
> 
> 1. The ink would not last through the etch.  At the time I think I 
> had tried to use a OHT marker (cut it off and used one of the 
plotter 
> pen bodies).
> 
> 2. When the pen would "land" on the copper, tiny ink droplets would 
> splatter and make a mess of the fine traces.
> 
> 3. The speed seemed WAY too fast to get nice dark lines that you 
> could get by hand with the same pen.
> 
> 4. Securing the board to backing paper.  As the plotter requires 
> paper to "grip".  (The paper movement also seemed WAY too fast and 
> would sometimes move the board out of registration.)
> 
> 5. The process seemed slow, and since I never got a decent board to 
> etch with this method, I abandoned it.
> 
> The plotter now once again collects dust in the closet :(
> 
> If you have any ideas to try, or like you said, software to try I 
> would be game to try it once again as I would like to get some more 
> use out of this practically new plotter.
> 
> --- In Homebrew_PCBs@y..., "caveteursus" <j.walton@a...> wrote:
> > like the HP7475a which I own, I've written some code to also use 
it 
> > as an XY pen-plotter.