Ivan,

Have you checked the plated thru hole to see if there are any
discontinuities in the plated copper in the hole wall?
Also, look for areas of thin plating, such as around heavy glass bundles,
drill gouges, etc.

Good luck,

Mike

        -----Original Message-----
        From:   Gary Camac [SMTP:[log in to unmask]]
        Sent:   Tuesday, October 12, 1999 4:07 PM
        To:     [log in to unmask]
        Subject:        Re: [TN] Blow holes on assemblies

        Ivan,

        Is the LEDs the only place your seeing the blowholes?  When you run
a bare board do the
        blowholes go away?  If you have eliminated the board as a source for
the blowholes,
        does the assembly sizzle when it is going over the wave?  If so, I
would suspect the
        more preheat might help.

        Gary Camac

        Ivan Barrios wrote:

        > I am currently having an issue with blowholes on TH components.
What I have
        > concluded is that the components are too tight and sit flush
against the top of
        > the board. When they go through wave solder, the outgassing has no
way to go but
        > down towards the wave solder. We have tried loosening up
components but then we
        > incurr having the LED's uneven after wave solder (and the LED's do
not match up
        > to the corresponding window in the enclosure) and are currently
looking for an
        > alternate LED that has standoffs so that the plated barrel is not
sealed at the
        > top. My question is: Is there anything that can be done process
wise to reduce
        > this defect? Thanks to all for your input
        >
        > Ivan Barrios
        >
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