As one response to Technet has already said the key is checking the
compatibility of the cleaning solution with the preferred paste. The paste
supplier should be able to define the best cleaning solution for the removal  of
wash offs and reflowed board if you need to clean them at any time.

You can buy a cleaning system and the machine will mechanically remove any trace
of balls and residues but that is not cleaning. You need to first define the
process which will allow the residue to go into solution with the cleaner in the
shortest time possible.

Manual hand cleaning only make it difficult for the chosen machine to get the
metallic particles out of the holes, via holes and resist windows. The paste
manufacturer then normally is blamed for causing solder balls after reflow when
they were there before the process started.

Bob Willis
Process Engineering Consultant
Electronic Presentation Services
2 Fourth Avenue, Chelmsford, Essex CM1 4HA. England.
Tel: (44) 01245 351502
Fax: (44) 01245 496123
Home Page: http://ourworld.compuserve.com/homepages/Bwillis
Email: [log in to unmask]


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