hi,

on the surface it surely seems unnecessary to wave solder this connector.
however, you might want to see if there might be a good reason for it.  for
example,  your customer might have learned that his press fit connector was
extremely unreliable. his (or her) approach to fixing this may have been to
require that the pins be soldered.  this scenario isn't likely, but who
knows?

phil

-----Original Message-----
From: Stephen R. Gregory [mailto:[log in to unmask]]
Sent: Tuesday, September 21, 1999 2:40 PM
To: [log in to unmask]
Subject: [TN] Okay, try not to laugh...


Hi Techies!

This one you'll get a kick out of. I've been working quite a bit in wave
solder here recently, and today an assembly that has been built once here
before (prior to me starting here) came down to my area to be waved
soldered.

It had suprised me to see the boards at wave solder because earlier I had
noticed that there was two right angle connectors being pressed into the
board. I asked why were they bringing me the boards and I was told; "To wave
the connectors..." (they were the only through-hole on the board BTW) "But
why?" I asked, "They're press-fit connectors!" The reply was; "Well, that's
the way we did them last time..." I tried not to laugh...honestly I
did...kept a pretty straight face actually.

So when ya'll get through laughing, tell me this, what kind of problems can
occur from trying to wave solder press-fit connectors...besides the obvious
barrel fill issues that come from the design of compliant-pin press fit
connectors keeping the solder from flowing up the barrel..."No wonder we had
some many solder problems last time.." I was told by a few of rework
operators here...kept a straight face on that comment too. (These are
Harting
press-fits by the way, a kind of triangular spade looking pin that almost
fills the whole barrel).

Me in my logic, thinks that since the connectors were pressed in, there's
got
to be some slight barrel deformation and/or strain put on the barrel walls.
Then running it across a 500-degree pot of molten solder just adds to the
strain from the thermal expansion it's going to see and could create some
problems.

Now I might entertain wave soldering a press-fit if I got a board in that
had
holes way out of spec and the connectors could be almost pushed in with your
hands. But these connectors have good contact throughout the barrel, and the
pins have been deformed (complied) with the barrel as they were pressed-in.

There's a rumor a-foot that some think we should wave them anyway so they
look like the ones we built before. I think that's almost the stupidest
reason I've ever heard to do something like that. I wanna know if there's
anything detrimental to waving these boards with a nice tight press-fit
already done...I think there is. What do ya'll think?

-Steve "I'm about to pull my hair out!" Gregory-

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