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Foam in the wash

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#50623

Foam in the wash | 12 June, 2007

We seem to have an overwhelming amount of foam produced in the initial rinse portion of our wash (enough to cause it to overflow). We are using an Austin American Hydrojet Mach III Inline Cleaner. To my understanding the first rinse of the boards is done with tap water and the final rinse is done with de-ionized water. We are using a de-foamer but that only works to a point and then makes it worse. Does anyone know of a better solution for this type of problem? Maybe filter the tap water or make the whole thing de-ionized? Also we are using a clay based mask that I believe is not the correct mask for this system and is also playing a role in this.

Thanks in advance.

Me

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#50624

Foam in the wash | 12 June, 2007

The presence of agitation at an air / solution interface and a foaming agent causes foaming. Most water soluable fluxes contain surficants. Surficants are foaming agents.

First, it's likely this foaming is caused by poor control of the temperature of the rinse water. Even a drop of 5*C may instigate massive foaming. Contact your flux supplier for a recommended temperature. In the meantime, we suggest a 50*C control point.

Next, as boards are cleaned, it forms water soluable soaps in the wash solution. These soaps appear as foam. This foaming may be surpressed, but only in moderation. If the soap concentration becomes too high, rinsing becomes difficult. In that case, excessive foaming is a useful warning to change the wash solution.

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#50628

Foam in the wash | 13 June, 2007

Hi Davef,

I noticed that you are always answering most questions ask by people in the electronic forum. I also noticed that your reply always hit the bulls eye.You are very good. It seems that you have the experience and the knowledged in the electronics industry. This is just a comment.

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#50631

Foam in the wash | 13 June, 2007

Awwww, man, now we'll never hear the end of it.

Actually, dave's a good guy and very knowledgeable about lots of topics to boot. There's just no overselling a guy that can appreciate foamy washwater, Cambrian fossils, and a nice Hefeweizan.

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#50634

Foam in the wash | 13 June, 2007

Brian, We had similar problem in our inline wash machine time ago. We checked everythin on equipment (filters, DI water purity, sprayers angle, etc). To make the long story short, we found out that the problem was caused by a new solder paste. This solder paste data sheet said "little to no foam" but for us was " a lot of foam". Maybe you want to try a different solder paste if possible.

My $0.02 George

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#50636

Foam in the wash | 13 June, 2007

Thanks everyone for the input. I think in our case Dave was correct in saying the temperature was the most evident casue to our foaming problem. I found out today from our maint. techs that temp. control has been an issue recently and now we know what needs to be fixed. Thanks again.

Brian

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#50637

Foam in the wash | 13 June, 2007

Do we puke now or masterbait?

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#50638

Foam in the wash | 13 June, 2007

Must be one of Davef's new hires. Someone feel a vacuum?

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#50639

Foam in the wash | 13 June, 2007

Whatever floats your dross bucket, baby.

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#50640

Foam in the wash | 13 June, 2007

"I've always dreamed of becoming a golf club."

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#50641

Foam in the wash | 13 June, 2007

"The world needs ditch-diggers too."

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#50661

Foam in the wash | 14 June, 2007

Interesting you say this since 99% of the people never respond on what the real solution was.....

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#50663

Foam in the wash | 14 June, 2007

One of the most pathetic displays of arse-kissing if me ever seen one me-self!

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#50667

Foam in the wash | 14 June, 2007

Brian,

We've see foaming issues with our wave flux occasionally when running large slugs of product through the wash. We love the wave flux and changing it was not an option. Our process parameters for the wash machine we're derived via a validation for medical products and are not subject to tweaking. SO - we ended up bypassing the input solenoid valve on the final rinse so it ran continuously. With a closed loop system, this allows the machine to recover very quickly between runs of product and the foaming problem is no longer a problem.

Good Luck.

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#50668

Foam in the wash | 14 June, 2007

Is the prewash water going to drain or being re-circulated? If you are re-circulating don't send all or a portion to drain (or your treatment system) even sending a small portion to drain and adding fresh will reduce foaming. You will pull more water but it will reduce foaming. Also if you add to much de-foamer it can increase the amount of foaming, weard but true. Make sure you follow the manufactures recomendations for the de-foamer.

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