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Aqueous Cleaning PCB's with Potentiometers

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#54505

Aqueous Cleaning PCB's with Potentiometers | 28 April, 2008

Hi guys,

do you have any issue aqueous cleaning pcb's with potentiometers? We have issues such as water penetrating inside the potentiometers causing shorts or electrical problem in the field. what is the drying temp and time you have in your experience in washing them?

thanks and regards,

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#54506

Aqueous Cleaning PCB's with Potentiometers | 28 April, 2008

I would contact the Part Manufacturer and get their Aqueous Cleaning Specifications for that specific part.

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#54507

Aqueous Cleaning PCB's with Potentiometers | 28 April, 2008

We don't clean open potentiomters

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#54513

Aqueous Cleaning PCB's with Potentiometers | 29 April, 2008

I second Dave response.

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#54522

Aqueous Cleaning PCB's with Potentiometers | 29 April, 2008

THANKS FOR YOUR REPLY GUYS...

more background...

solder paste is Water Soluble. We mask the potentiometers prior to aqeous washing using solder mask, then our operator brush the solder joints with IPA after the Wash Process...I'm concerned about the long term reliability of the solder joint not properly washed by DI Water.

Is brushing with IPA acceptable to remove WS Flux on the termination? what issue will it pose in the future aside from corrosion?

thanks again...

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#54526

Aqueous Cleaning PCB's with Potentiometers | 30 April, 2008

It's not acceptable to us. More importantly, you need to determine if it's acceptable to your customer.

Recognize that your little IPA scrub does NOT remove the OA flux residues from the board. It mearly spreads them out across the board and under components. We have ranted on about this practice here on SMTnet previously. So to spare others from more of the same, search the fine SMTnet Archives for more, if you're interested.

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#54529

Aqueous Cleaning PCB's with Potentiometers | 30 April, 2008

If your pots are open you then just need to dry them. Don't hide them. Are they rated for water clean? If not hand solder after cleaning with no-clean wire.

Hand cleaning with IPA is dangerous - you really just push the flux around and don't wash it off.

Most cleaners have options of dryers for them. This with may a heated dryer unit is probabaly the way to go.

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