In a message dated 9/21/99 6:42:13 PM Central Daylight Time, [log in to unmask]
writes:

> Steve,
>  I thought I have seen/heard it all while working at IBM. This tops them
all.
>  Yes, there can be serious issue with deformed PTH barrel and outgassing (
> with resulting
>  solder balling) during wave solder. This is true if there are cracks in
> plated copper.
>  What type of compliant pin are you using? 'C' type pin may a little
> forgiving than
>  other types ( paddle, star etc..)
>
>  Test solder a board and xsection the connector joint(s) to show your
fellows
>  (management) the effect it may have on field reliability. Please post the
> results.
>  Good luck.

I guess I may not have said what I really meant, the barrel is not deformed
from what I saw when looking at the press-fit pins under a microscope. I was
just thinking in terms of what happens when you press a press-fit connector
in. Copper being such a ductile metal will deform at least a very small
amount when any pressure is applied.

The barrel walls have been plated with tin/lead, and inspecting the
pressed-in connector you can see that the pin of the connector has indeed
embedded itself into the plating. I've got no major "tin-foiling" appearance
of the pins that happen when a hole diameter is too small and pushes out at
the tip of the pin...just a nice tight fit...the way things are supposed to
be with a press-fit connector.

I'm just worried that because things are so snug (just like they're supposed
to be with a good press-fit), that passing the board over wave and the
thermal excursion along with the expansion that the board will see, along
with all the 800-degree tip soldering irons that'll be all over the place,
I'll be creating damage to the boards.

To be perfectly honest, nobody has ever heard of, and understood, press-fit
technology here... "WHAT? Send a board out without soldering it? I've never
heard of such a thing!"

Maybe you understand what I'm up against...

-Steve "Bald" Gregory-




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