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

--- 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.