Daan,

It may not apply, but we had these problems when the flux in our wave solder
became old (and needed replacing).  Once we cleaned the fluxing system and
used all new flux the problem would go away... until it was time to change
the flux again.  The white residue is tough to get off too.

Phil Nutting
Manufacturing Engineer
Kaiser Systems, Inc.

-----Original Message-----
From: d. terstegge [mailto:[log in to unmask]]
Sent: Tuesday, May 01, 2001 11:27 AM
To: [log in to unmask]
Subject: [TN] white residues after cleaning


Hello Technet,

We've got some expensive boards here with white residues after cleaning.
Most of it is invisible for the naked eye (conforming IPC class 3
standards), but each board has a  few small spots that are visible (if you
look really good).
Now the customer wants proof of what this residue is. Not because they can
see the residue, but because they know it's there.
These are double reflow boards, soldered with RMA solderpaste. After each
soldering step the boards are cleaned with Axarel 32 and rinsed with
deionised water.
Our ionograph shows that there is hardly any ionic contamination on these
products.

Some questions:
1)  When there's so little residue present, will it be possible to do an
analyses ?  To collect a few grams I'd have to scrape the residues of
hundreds of boards !
2)  What kind of analyses should be done ?
3)  Any recommendations on where to have the analyses done ? Locations in
Western Europe are prefered.

All answers are more than welcome.

Kind regards,

Daan Terstegge
Thales Communications
Unclassified mail
Personal Website: http://www.smtinfo.net

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