Hi John,
What about a small rotating burnishing tool, so the "scratches" would
have some width? I can see that this would be very similar to milling
the isolation traces.
Alan KM6VV
P.S. Heard you've got a new mill/plotter working? pix?
crankorgan wrote:
>
> Hi Alan,
> Layout blue is made to be just scratched. It has been around
> for 75 years. The trick is to have your traces drawn with an overlap.
> During the scratching process you can be sure the trace is isolated
> cleanly. The only drawback is all the traces are surrounded by a
> ground plane. This is the same result as milling them. I use the
> ground plane for my ground connections. Most digital circuits work
> just fine with the extra copper. High end receivers use ground
> planes. There is no simple way to make a PCBoard. Even sending them
> out can have headaches.
>
> Cranky
>
> --- In Homebrew_PCBs@y..., Alan Marconett KM6VV <KM6VV@a...> wrote:
> > Hi Brian, John,
> >
> > What about using a diamond engraver tip? I bought one (mistakenly)
> > thinking it was for machining (it was for the Dremel engraver).
> But I'm
> > thinking one could drag it around as well. I can "read" Gerber
> files
> > with my controller program, and I generate "outline" tool paths.
> from
> > that.
> >
> > Alan KM6VV
> >
> > Brian Schmalz wrote:
> > >
> > > Crankorgan,
> > > Putting bluing on the whole board, then scratching it off
> with a
> > > carbide metal scratch tip is the method I'm currently using to do
> boards. I
> > > tape the copper down on a piece of paper, then run it through my
> HP plotter
> > > (7550A). I get very clean lines and can get down to 10mil space
> 10mil line
> > > with a bit of practice, double sided. I've written custom
> software to take a
> > > Eagle board file and create HPGL which I then output to the
> plotter. This
> > > method really works well since you can use a standard plotter (I
> just built
> > > a special 'pen' with the carbide scratch tip) plus some software.
> Anyway,
> > > the bluing/scratching method is alive and well . . .
> > >
> > > ∗Brian
> > >
> > > -----Original Message-----
> > > From: crankorgan [mailto:john@k...]
> > > Sent: Saturday, September 14, 2002 6:41 AM
> > > To: Homebrew_PCBs@y...
> > > Subject: [Homebrew_PCBs] Re: Inkjet printing PC boards
> > >
> > > Larry,
> > > I sell plans for a PCBmill (Brute) and I just finished a
> > > machine that will mill or draw simple boards. (Morph)
> > > Months ago I brought up the idea of Scratch and Etch. This
> > > idea is not dead. First I developed a super simple CNC plotter.
> Now
> > > I have a machine strong enough to drag a scribe through the
> blueing.
> > > Several people tried Scratch and Etch With good results. Coating
> the
> > > whole board and then scribing and isolation between pads for
> etching
> > > seems easier.