In a message dated 98-07-30 16:45:10 EDT, you write:
<< Hi Jeff
Always thought that closeness of SMD components to scorelines was a much
neglected subject. In another life I had some bad bad experiences with
this....
Wolfgang / Viasystems Canada
> BTW Mark,
> I notice that there are no references to guidelines for
> closeness of SMD components to V-score edge..any feedback from the
> industry or feelings for this subject you would like to share
(please,please).
> How about anyone else out there?
> Regards & Thanx!
>
> Jeff Hempton
> United Technologies Electronic Controls
> >>
Hello Wolfgang, and Jeff!
If you want to talk to someone who has done a study on exactly that subject,
call a gentleman named Dennis Johnson at: (510) 262-8990, he's the owner of a
company named "Onanon", and what they do for a living is nothing but drilling,
scoring, and routing. Dennis was asked by 3COM to determine how close they
could put a capacitor to a score line and not worry about damage during
singulation, and that's exactly what he did.
Dennis and his company bailed me out one time when we got a consigned job that
had scored panels. Problem was, the fabs we recieved weren't scored deep
enough.
Even worse, that little tidbit of information wasn't discovered until after
the boards were built (says something about our customers incoming recieving
inspection don't it?). So this was just peachy, we got the boards built, but
couldn't get them out of the panel. Dennis was able to pull a rabbit out of
his hat, and go back and re-score them to the proper depth with the boards
loaded. Needless to say, I owed him a few lunches for that one.
He's also developed a chart that you can use to determine what a good depth
for scoring is. It's based on what the laminate thickness is, and how big the
individual PCB in the panel is, and it really works! I use it every time I
need to come up with a scoring spec, and it hasn't once let me down. I've used
it mostly with PCMCIA, and SIMM panels.
-Steve Gregory-
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