Ken,

This could be a heat related problem or flux related but from what you said
about getting better results when using a foam fluxer I would suspect the
flux.  The flux may not be active enough or just not robust enough to
survive the preheat and dual waves.  More details are needed to fully
unserstand your process.

Ken Kirby





 (Embedded
 image moved   Kenny Robertson <[log in to unmask]>
 to file:      10/08/99 07:27 AM
 pic10562.pcx)




To:   [log in to unmask]
cc:    (bcc: Kenneth Kirby/ElectrovertUS/Cookson)
Subject:  [TN] (Fwd) Topside wetting on Gold PCBs




------- Forwarded Message Follows -------
From:          Self <RobertsK.Eng.Perth.UK>
To:            [log in to unmask]
Subject:       Topside wetting on Gold PCBs
Reply-to:      [log in to unmask]
Date:          Thu, 7 Oct 1999 17:13:56 GMT

Hi,

I am currently processing an immersion gold finished card through
bottom side glue, topside reflow then wave solder.
The problem I am seeing is solder is not flowing through to the
topside leaving many PTH parts with very little hole fill. The wave
solder is an Electrovert Ultrapak with  econo spray fluxer twin
preheats and dual wave.
I have tried running the boards through an older machine which has a
foam fluxer and this gave improved results but still not perfect.

Has anyone seen a similar condition and what was the solution.

Ken Robertson

Telspec Scotland Ltd.

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