In a message dated 12/14/2006 4:24:06 P.M. Eastern Standard Time,  
[log in to unmask] writes:

Further  still, how does one panel get screwed-up like this and not  the
others?


 
____________________________________

 
Hi Steve:
 
That's an interesting picture. I decided it might be best to look at the  
photo from the perspective of a client asking me to deliberately create  that 
particular effect (and with a gun pressed firmly to my head).
 
For me, it keeps coming back to drill. I could create something like that  
through controlled depth drilling. And it can also be done accidentally. Here's  
1-way how:
 
Most low(er) tech PCB designs permit stacked mechanical drilling. Typically  
on .062" material a Fabricator can drill 3-high (.062" x 3) with reasonable  
results. However, if the drill bit were to slip in the collet it's possible the 
 drill might not penetrate through all three stacked PCBs. If it went through 
the  first two PCBs but only partially through the bottom PCB, the effect 
would be a  partially drilled exit aperture with a pronounce lip.
 
This theory also offers an answer to your question, "...how does  one panel 
get screwed-up like this and not the others? By only affecting the  bottom 
panel, most of the product continues unaffected. As for it being only  1-panel 
(so-far) it's possible that the Fabricator actually caught the  error and 
reworked all but 1 panel (the notorious "escapee").
 
It's required to note that E/T wouldn't catch this as the  PTH is likely 
fully functional electrically.
 
It may also be interesting to note that while most drill machines have  
devices or sensors for detecting broken or missing drill bits, not all have the  
ability to critically monitor drill bit length.
 
While I may be way-out with my suggestion, I'll hang onto it  until a few 
more pictures show different angles (or folks more sane and  experienced have 
time to respond).
 
Until then -
 
Bob
 
ROBERT LAZZARA
VP, Business Development
T: (800) 560-9457
F:  (800) 878-5566 (y servicio de mensaje español)
E:  [log in to unmask]
W:_  www.CircuitConnectUSA.com_ (http://www.circuitconnectusa.com/) 



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