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Cleanliness: Cross Contamination of Flux

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#51769

Cleanliness: Cross Contamination of Flux | 12 September, 2007

We've configured SMT and Wave lines such that each line can run either No-Clean and Water soluble process. As we are doing cleanliness study, an observation is there may be cross contamination when we share the Rework benches or PCB trays between No-Clean and Water soluble. Hypothesis is trays or benches may transfer active ionic elements possibly from water soluble boards and contaminate No-clean assemblies. Do you have any experience or knowledge of such concerns?

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#51775

Cleanliness: Cross Contamination of Flux | 13 September, 2007

After receiving either a water soluable or low residue soldered board for rework, in a real life work environment, regardless of the quality of the documentation, we can picture it a bit confusing for troop to consistantly select the proper combination of: * Wire solder, both water soluable and low residue * Flux, both water soluable and low residue * Soldering iron, one each for water soluable and low residue * Sponge, one each for water soluable and low residue * Cleaning procedure

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#51786

Cleanliness: Cross Contamination of Flux | 14 September, 2007

Thanks davef. Your comments are well taken. How about the trays transporting boards from one station to another or staging at WIP Kanban? It��s easy enough to segregate rework stations and tools. Trays are used thru out the plant without segregation except for Pb and Pb-Free. It would be difficult to implement and maintain 4 different trays; Pb/Pb-Free, Water soluble/low residue. I'm speculating with no evidence at this point that this could be one of source of cross contamination. I may clean the mat and trays periodically but it's difficult to decide the frequency. Have you heard of any cross contamination issues? What do you think how it would affect if I share the trays?

Thanks.

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#51789

Cleanliness: Cross Contamination of Flux | 14 September, 2007

Sure, it's possible to transfer water soluable flux from boards to tray to boards with low residue flux. We have never heard of this try of problem.

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