Steve,

V-grooving option is not very good unless you have a
depanellling machine.  To relieve your concern for multilayer
boards, try the following three options:

1. Make the web thickness of V-groove to 0.2mm to 0.3mm.
This is ideal for light assemblies and allows easy break of
boards without stress.  However most board vendors don't
like to cut too skinny.  They prefer approx. 0.8mm.

2. Make routing as you said.  Keep routing gap to 2.4mm
and tab width to 1mm.  This allows straight-hand cutters to
go in and cut out tabs withour bending/break.

3. Specify lazer-score.  Very easy to break and good for light
assemblies.

Make sure you have 1mm space btw board edge to nearest
conductor/layer.

regards
Matthew

>>> Steve Collins <[log in to unmask]> December
15, 1997  2:00 pm >>>
I have a design that lends itself to being V-Grooved but I
seem to recall
either in a Forum discussion of a personal discussion that
this could be
dangerous for multilayer bd.. The reason would be that it
would be possible
to fracture an internal layer with the V-Groove panel style.
When I think
about the alternative which is to rout the board it seems to
me that the
same danger is present when you break the boards away
from the tabs present
on the panel. Does anyone else have a feel for this or have
experienced any
of the things I has discussed.

Steve Collins

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