Sheila,
I would first look at your flaring process.  When I experienced this same
problem in a previous life, I found that the operators were pressing the
terminals too tight into the PWB.  Of course, when the PWB heats up during
the wave solder process, expansion occurs, thereby causing the stresses that
you are seeing.  What we found was that the terminals did not have to be
tight before the soldering process.  As long as the terminal could spin in
the PTH w/o much z-axis movement, measling did not occur.  Good luck.

Rich Buccieri
tyco Packaging Systems
(Formerly AMP Packaging Systems)
Phone:512.671.5555
Fax:512.671.5842
Email:[log in to unmask]



> -----Original Message-----
> From: Sheila Smith [SMTP:[log in to unmask]]
> Sent: Tuesday, April 13, 1999 10:16 AM
> To:   [log in to unmask]
> Subject:      [TN] ASSEMBLY:  measling around pressfit flared hardware
> after wave solder
>
> Hi TechNet,
>
> We have a small multilayer (4, I think) GFG board which has 8 pressfit,
> flared terminals installed along one edge, about 0.25" from the edge of
> the board.  After wave solder,  these boards are being rejected for
> measling around the hardware - typically between two terminals.  The
> measling was either not present before solder or was made more apparent by
> the wave solder temperatures.  The hardware is the correct size for the
> board thickness and hole size & is being installed using the
> manufacturer's tool.  We did not observe this problem in previous batches
> but the board material has been changed from FR4 to GFG [should have
> helped, I'd think].  Is it possible we are doing mechanical damage to the
> boards during flaring?  Thanks in advance for your help!
>
> Sheila Smith, Marconi Aerospace
>
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