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DON'T KNOW IF THIS WILL HELP.
BUT, MANY YEARS AGO WHITE RESIDUE WAS OBSERVED ON COMPONENTS THAT HAD
BEEN FLUXED WITH A HIGHLY CHLORINATED FLUX.. IT WAS DETERMINED TO BE
SOLUBLE "ONLY" IN A DILUTED SOLUTION OF THE ORIGINAL FLUX..
SORRY, THAT'S ALL I CAN OFFER.
______________________________ Reply Separator _________________________________
Subject: White residue/lead oxide
Author: [log in to unmask] at smtp
Date: 5/7/96 10:16 AM
We have a white residue problem at another division that has been analyzed
using FTIR and SEM EDAX that has shown it to be lead oxide. The white residue
is located on pads/solder fillets. The following process is used:
a. Yokota flow solder (preheat 220F topside, 495F solder pot (less than 3
seconds), conveyor speed 3.5 ft/min)
b. Kester 197 foam fluxer (rma)
c. Cleaner is Bioact EC7R in a Ney spray under immersion or ECD batch
diswasher. Temperature of EC7R 90-95F, Rinse waters 130F.
The white residue is observed after cleaning and is insoluble in alcohol
water/EC7R.
Any input on things to look for would be greatly appreciated. We are running
tests at other divisions with different flux chemistries/board design/process
parameters.
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