Hi Angie,

We have a backplane board with several PCI connectors and do not experience
warping during wave solder. Our board is not as wide as yours, however. If I
had to guess without more info, I would say the warpage is due to the large
size of your board and the weight of components on it caused by the pcb getting
soft during wave solder (this assumes that the warpage you are seeing is the
board bowing down in the middle). If that is the case, the board will need
support. Perhaps the most convenient way to do that is to use a wave pallet or
fixture such as that used for selective wave. That would open up areas for the
PTH parts to get soldered while the rest of the board is supported by the
fixture. We use a fixture on the board I mentioned above.

Regards,

Denis Mori


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-----Original Message-----
From: Non-HP-Peebos /HP-Roseville,[log in to unmask]
Sent: Friday, December 11, 1998 6:23 PM
To: Non-HP-TechNet /HP-Roseville,[log in to unmask]
Cc: Non-HP-Peebos /HP-Roseville,[log in to unmask]
Subject: [TN] Warped boards at PCI connector?

To technet
I have this board that is 18 by 14 though hole and SMT. After reflow the board
looks good not warped. Once assembled and sent to wave the board warps, only
around the PCI connectors. It warps so bad I don't have any lead protrusion. I
have tried to run this board many ways fast slow and minimal preheat. I still
have this problem. Has anyone ran into this problem before? Is this common
around PCI connectors? I recall this happening once before many years ago, I
resolved it by tacking down the edge and middle of the connectors then
masking. Is this the only fix? Any other suggestions

Thanks in advance
Angie

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