interesting question...

We use breakaway rails on our rigid-fex, with perforated tabs.

The funny part is we never let our assy vendor USE the perforations
to "snap" off a rail, they are explicitly instructed to use a router,
or in rare cases (like a prototype run) they have a little hand-
held nipper to depanel. I suppose we only have them in case WE
want to depanel one in the lab or something.
You said this piece would not be used in production, but it is
still quite easy to bend/crack components or tear flex, so they
better know what they are doing. Also, you might want to put
some fake copper along the edges of the flex to keep a tear
from starting. Once it starts, it doesn't stop....

p.s. We use Regal-Flex/HVRflex so we don't have flex material
in the rigid portions of the design, but I would bet if you use the
perforations you can break it with no trouble.

good luck,
Jack
.


On 1/8/07, Scott Riley <[log in to unmask]> wrote:
>
> I've got a 6 layer rigid flex design with the rigid portions being on each
> end and two flex layers joining them (picture a barbell).  The customer
> wants an additional board attached to one of the rigid portions that will
> be
> "snapped off" at a later time. There is no circuitry running between these
> two pieces.
>
>
>
> I'm not sure how well the polyimide that is sandwiched between the FR4 is
> going to "snap off".  I told the customer that it is made to flex and will
> most likely remain connected. I'm thinking about making perforated
> breakaway
> tabs, but think the flex material may still need to be cut somehow.  The
> boards would be assembled prior to separation.
>
>
>
> Does anyone have any experience with something like this ?  This is for
> development and would not be used in production, quantities would be very
> small.
>
>
>
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