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November 2004

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Subject:
From:
Tom Gervascio <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Tom Gervascio <[log in to unmask]>
Date:
Wed, 3 Nov 2004 14:33:00 -0500
Content-Type:
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text/plain (40 lines)
THe question is why does the connector shift? Is it due to warping of the connector, the board, oven or conveyor transport vibration, due to uneven melting of the solder- similar to tombstoning of chip parts- in the oven. We had a TO252 that would shift when it went into reflow because of uneven thermal mass connected to the pads. We added a water soluble mask across non soldered areas of the parts and then wash off the masking material. Don't get it on solder paste. Not elegant but it would work.

my $0.02 worth

Tom Gervascio
Senior Process Engineer
Sparton Electronics
(352) 540-4040

>>> [log in to unmask] 11/03/04 01:39PM >>>
Hi all,

Looking for recommendations on ways to keep an SMT connector from shifting
during reflow.  This particular connector does not have any guidepost to
help keep it in one place.  Is there any special pad design that can be
incorporated to help assist with keeping the part in place during reflow?
The pads are currently rectangular shaped.

Jim

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