Re: CNC v-groove routing for PC board scoring?

I've done the tab routing before (I have just the router bit set you
describe...) but the reason this needs to be v-scored is for
compatibility with the depanelizing machine at the assembly house.
Also, the boards are very small (on the order of 1/4" x 1/4") and the
scoring makes the most sense.

I agree about the need for strict flatness and depth control. Depth
won't be a problem on my mill but even though I'll have 4 tooling
holes on the board I may add an additional hole in the middle to tie
things down.

I also plan on setting up an old board to experiment with and get my
heights adjusted correctly.

Thanks for your input!

-Jeff

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "caudlet" <thom@t...> wrote:
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Jeff Swayze" <jswayze@o...>
> wrote:
> > Hi Folks,
> >
> > I'm looking at having some cirtuit boards made but I want to save
money
> > and do the v-groove scoring myself. For those not familiar with
the
> > process, a v-groove is cut in the top and bottom of a circuit
board so
> > there is a small web left in the middle. Once the board has been
> > populated a wheel-type cutter breaks the board along the score
lines
> > and separtes the sub-boards from the main board.
> >
> > The real machine that does this uses a saw blade-type cutter that
has v-
> > shaped carbide tips on each tooth. This would require a
horizontal mill
> > (which I don't have) so I bought a carbide v-router bit from a
> > woodworking store.
> >
> > I'm basically wondering if anyone else has tried this or could
point me
> > to a discussion or a website that talks about this technique.
> >
> > Thanks,
> >
> > Jeff
>
> Jeff they make chisel tooth router bits for PCB edge routing. I
> ususally end up with several in one of those cheap assortments you
can
> get. You could edge route the cards and leave breakout tabs that
could
> easliy be cut by hand maybe even after you stuffed the boards.
>
> The latest version of SheetCAM allows you to pick a contour, define
it
> as inside or outside to have the right tool offset and then place
tabs
> alond the cut of the size and frequency you want. Cutting with V
bits
> is a delicate process since the width of the cut is directly
> porportional to the depth and if your board is the slightest bit
> raised or lowered, the width will be different. No big deal when
you
> are chip carving in wood but trying to hold a straight edge is going
> to call for very precision height control and flatness of the
> material. He also provides a Excellon file import but I don't know
if
> it will do the edge routing. If you build in registration holes in
the
> panel then you can place it on pins for doing the edge routing
using a
> conventional drawing and CAM approach.