In a message dated 8/19/98 7:03:00 AM Pacific Daylight Time, [log in to unmask]
writes:

<<  I am in the process of converting a PCB from Through Hole to
 SMT.  Of particular concern  is the fact that in use, the board
 is held along its edges while a connector is plugged into the
 PCB.  I am concerned about PCB deflection which will result
 in stress to the SMT components and solder joints, causing
 hard and/or latent defects. >>

Hi Mike!

     I know somebody who you can probably get some good information from, his
name is Dennis Johnson of Onanon. His company does nothing but drill, route,
and score PCB's. He does a few other things too, but mainly PCB's.

     A few years back, he was asked by 3COM out here if he would do a study to
determine how close you could put a SMT capacitor to the edge of a score-line
on PCMCIA panel, and it not suffer risk of fractured joints when depanelizing
the board.

     From that study, he developed a easy to use chart to determine what score
depth one should specify for varying laminate thicknesses, to ensure easy to
separate panels after assembly, but yet don't fall apart when you're half-way
complete building the darn things...I HATE it when THAT happens! (GRIN)

      I'm sure if there's anything about board flexing and solder joints you
wanna know, Dennis be da man!!

His number is: (408) 262-8990    Email:  [log in to unmask]    Web:
www.onanon.com


-Steve Gregory-

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