On 28 April, 1998 Steven Sauer wrote:

> 4. Be wary of your glue dots. If you choose to use double dots for chip
devices, ensure that > after the component is placed that a dam is evident. If
a dam is not present, a stream of
> flux residue, solder, or other contaminates can reside under the component
and cause
> current leakage and possible shorting.Look at the archives on this subject
(roughly 6
> months ago we had a discussion on this or it may have been on the SMTNET).

Hi Steven,

     I remember that discussion, it was pretty enlightening. Along those
lines, I do have a question about something that I've seen on a few boards in
the past...

     There's been boards I've run across where the designer added (or left in)
a small strip of copper in between the pads on the bottomside locations. I
didn't know what they were at the time, but after learning a few things about
the shorting issues that occur during wave, I think maybe those little strips
of material were there to possibly prevent that.

     I know whenever I ran boards that had those features, I would have to
decrease the amount of glue I was dispensing otherwise I would lift the part
off the pads during cure. Has anybody else seen or heard of a design practice
like that? Does it prevent the kind of shorts that have been discussed?

                             Just curious...

                            -Steve Gregory-

P.S. Thanks everybody on the suggestions about how to care for a
      conductive tiled floor, it was most appreciated!!

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