Homebrew PCBs

Hi Steve,
         When you use a plotter to draw on the copper
you have to be able to slow the plotter down. If you
don't the ink will not flow fast enough. Over the years
I have made PCBoards with every method. Mechanical Etching
has lots of pitfalls too. My latest one to show up is runout
of the Dremel. For over a year I milled at 16,000 RPMs. Then
I made a stiffer machine. I set the speed of the Dremel faster
and I increased my feedrate to 8" per minute.  I got several
boards milled with no problem. Then everything went bad. In
the end I found that you should set the Dremel at 16,000 RPMs
with a feedrate of 6" per minute.  With a bit in the Dremel turn
it on and look at the tip of the bit. When you increase the Dremel
past number 3 you will see the tip of the bit grow. This is
caused by centrifugal force and a worn bearing. My Dremel has
many hours on it! The tip of Mechanical Etching bits grows twice
as large above 16,000 RPMs. I am going to buy a new Dremel and
check it out. Mine has paid for itself several times over and
its time for a new one.  


                                    Nachbauer


--- In Homebrew_PCBs@y..., Steve Greenfield <alienrelics@y...> wrote:
> Good point about speed of pen-up and -down. Oops, you're
> Kleinbauer. I know a Nachbauer who makes Theremins, hence my
> mistake.
> 
> I did try a Staedler 313 (Red) pen, just discovered I already had
> one. I was etching some boards I'd made with a vinyl cutter and so
> I drew onto a bare area with the Staedler 313 and some permanent
> pens, the kind they sell at Radio Shack remarked as "Etch Resist".
> IE, laundry marking pens.
> 
> My acid (Ammonium Persulfate(sp?)) was weak so it took a long time
> to etch. The laundry marking pen started out with a few breaks, and
> ended up pretty bad. The Staedler 313 was nearly perfect. That was
> just me drawing it, I'd expect better from a plotter moving the pen
> at a more constant speed.
> 
> The vinyl cutter? I drew it in CorelDraw and cut it out of vinyl
> sign plastic and stuck it to the board. I didn't do nice traces, it
> was done as large areas of copper isolated by thin etched strips.
> This was at the limits of small size of the cutter and the vinyl.
> 
> Steve Greenfield
> 
> --- crankorgan <john@k...> wrote:
> > Steve,
> >       Don't take the plotter apart until you look at:
> > 
> > http://www.qsl.net/ve2emm/pcb/pcbe.html
> > 
> > 
> >        Also, hooking up a Dremel or other tool to a Plotter
> > has a drawback. Pen-up and pen-down signals are too fast. If
> > you use a dashpot to slow the solenoid, the X Y will start moving
> > before the Dremel is down all the way. A plotter can make really
> > nice boards. It is possible to gut a plotter and drive it using
> > GCode files. Then using the Z axis movement you can get the
> > timing
> > right.
> > 
> >                                                John
> 
> 
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