Hi Alan,
I mount a 8" X 8" piece of 1/4" PVC to my bed
using four flat head 10-32 bolts. I run the machine with
an old Mechanical Etching bit in it. I cut a fine "L" in
the plastic. In the "L" I drill and tap 2-56 bolt holes.
I then place a PCB under the bolt heads. This helps me
locate where the other screws go.
The board is held down on all sides with just the
bolt heads. If you use a 60 degree Mechanical Etching bit
variations in copper and board will not be a problem. This
is if the board is cuped up! The single sided ones I buy
are.
My machine will do a trace between a pad. Two traces
between a pad!!! No way! I have seen the sample boards on
those site. Show me the boards made by regular people using
their machine. No burrs either, just perfect traces.
The boards I use have very thick copper. If I get
the money, I will try some PCB made for Mechanical Etching.
John
--- In Homebrew_PCBs@y..., Alan Marconett KM6VV <KM6VV@a...> wrote:
> Hi John,
>
> Good tips! When you bolt your boards down, how much deviation is
left?
> I just looked at LPKF (again, for the 1000th time), and they are
VERY
> precise! TWO traces between pads. And I'm thinking that if the
depth
> is controlled more closely, bit life will be improved.
>
> Alan KM6VV
>
>
> crankorgan wrote:
> >
> > Hi Alan,
> > I see that! I use the heads of 2-56 bolts to hold
> > my boards down. The ones I buy are cuped foil side up. They
> > are 4" X 6". The bolts go into a piece of 1/4" PVC. I find
> > holding the board by the edge-the best method so far. Since
> > all my boards are 4" X 6" I only have to take two bolts out
> > and the board slides out the end. The bolts pull the board
> > down flat. When I do smaller boards, I have other rows of
> > taped holes in the PVC. The Tit4Tat board was 1/2 of the
> > 4" X 6" board. I would make two at once. I used to make 4
> > 1 axis boards out of one 4" X 6". Tape is fine for doing
> > a flat pcb, but most surplus boards come warped.
> > How would I fix a warped board when making a double
> > sided board? Simple, use one or two bolts in the middle of the
blank.
> > They then become mounting holes.
> >
> > John
> >
> > --- In Homebrew_PCBs@y..., Alan Marconett KM6VV <KM6VV@a...>
wrote:
> > > Hi Listies,
> > >
> > > Some activity on the CCED list about LPKF and holding PCB's
down to
> > mill
> > > them. Anyone here have the LPKF system?
> > >
> > >
http://www.lpkfusa.com/products/product/rapidpcbpro/index.htm
> > >
> > > I'd like to get a closer view of the Z height "tracking donut"
on
> > this
> > > machine. And, I'm in the process of downloading a demo of their
> > > program.
> > >
> > > Alan KM6VV
> > > P.S. I'm also looking at a low-cost Gerber to Gcode translation
> > program
> > > that should be available soon! More details when past beta.
> >