I'm not sure I followed all this exactly, but in a former incarnation worked
on problems which sounds familiar or at least relevant. Used to do intricate
routing and sometimes correction on softstrates like FR4 with laser
profilers.
This route would involve finding someone who could really drive a laser - to
get a good edge. You would also need deep pockets. Lasering is relatively
slow (for cutting not scoring) and boards can only be processed one high.
For example, our standard [show off] question on being asked to rework
too-shallow v scoring: "do you want to drawing in which case you will get an
extra cut, or you can tell us where in the actual V you would like it, most
people go for the bottom, but you can have in the side of your choice." This
was because a laser beam has very little dimension and x-y table/control was
very precise with good vision.


Regards

Mike



-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Mark Hargreaves
Sent: Friday, December 20, 2002 1:51 PM
To: [log in to unmask]
Subject: Re: [TN] FAB: Edge Plating and Burrs after Routing


Hi All,
We faced the same fab challenge (I think) earlier this year.  We called it
the half hole board from _ _ _ _!
Internal rectangular cutout (non edge plated) which bisects 28 plated
through holes (dip pattern).
Tried various router bits & paths. Tried small pilot holes to cut the plated
holes prior to route.  Tried routing the cutout after Blackhole but before
copper plating.  This worked best.........except for a thin surface shorts
like those that John P. encountered. (sound familiar)?
Kicking myself for not consulting this esteemed forum at the time.  Good
money job if we could have made it.
Water...........who'da thunk it !

---John.  please provide feedback if you decide to go this (route).

Regards & Happy Holidays,
Mark H.





        High pressure water jets are the coolest thing to watch.  Definitely
something that electronics could use in many applications.   Here's another
source for water cutting technology: www.jetedge.com

        Kathy


        Hi John,

        There is a process that can do a beautiful job but it is not well
known in the PCBs and electronics industries. The process is "Cutting with
high pressure water jet". The problem is that the equipment is expensive. I
am sure you can subcontract this process. There is a PCBs shop in Illinois
that has this machine, I do not know if they accept subcontracting. There is
also a manufacturer of this equipment in Seattle, not far from you, that
either can subcontract the work for you or refer you to some one who can.

        You can contact me off line and I will give you the info for these
companies.

        Merry Christmas and happy Holidays to all.

        Sherif Refaat


        Greetings all,

        I think it is time to throw this one out again to all you fab guys
out there, especially since we have yet to come up with a way to do it.  I
don't think a solution has ever been presented on this forum but I keep
hoping :o)

        Has anyone come up with a way to produce an edge plated feature that
mates up to a non-plated edge without producing a burr after routing AND
with no manual finishing required after routing??

        We have tried various rout paths and cutting tool types without
success.  We even tried a good idea presented on this forum some time back
which was to rout after electroless copper.  What we found here though was
(and this may be hard to describe) that we ended up shorting the features
together (lets assume that we are routing through an array of plated holes
on the edge of a board which need to be isolated electrically from one
another) by a thin strip of plating along the leading edge of the panel.
The reason for this is that the exposed edge (exposed by the post
electroless rout) of copper (on the surface of the panel) while covered on
its surface by photoresist still picks up copper and tin plating.  The tin
of course then prevents this thin strip from being etched off resulting in
the short.

        Hopefully you can follow that one.  Anyway, any suggestion?

        Best Regards & Merry Christmas
        John Parsons

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