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Date: | 7 May 1996 10:16:16 U |
Content-Type: | text/plain |
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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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