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Water Soluble Flux

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#63204

Water Soluble Flux | 29 November, 2010

Dear all Can any1 explain me about the variuos types flux and their cleaning procedure? I have confusion in claen,non-clean,RMA, and water soluble.

Thanks in advance.

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#63211

Water Soluble Flux | 30 November, 2010

A simple question with very complex answers...

But to simplify, you could start at this.

Water soluble fluxes are cleaned using (typically) de-ionized water, using a spray wash method. Sometimes a saponifier is added to the water to help it get into tight places. These fluxes can range from active to VERY active.

NoClean Fluxes are just that. They are designed to be processed and then left in place on the PCB, saving the wash step. When used correctly the flux residue is OK. Does not look pretty, but is OK. These fluxes are typically not too active, have less active ingredients by their basic nature.

RMA fluxes are typically VERY active, and must be cleaned from the PCB rather quickly using a solvent method of some kind.

These are very basic outlines. The question is huge, really.

Hope is of some help.

'hege

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#63212

Water Soluble Flux | 30 November, 2010

There are also No-Clean/No-Residue fluxes where the flux gets eliminated by the heat of the soldering process (this eliminates “does not look pretty” in hegemon’s post).

Patrick http://www.interfluxusa.com

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#63215

Water Soluble Flux | 30 November, 2010

Patrick is an expert, and is of course correct.

I was oversimplifying the answer. There are a number of NoClean fluxes that leave little to no visual residue, and would be classified as "pretty"

Thanks Patrick

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#63219

Water Soluble Flux | 1 December, 2010

Thank you, Patrick and Hege

I now more understood about no-clean and RMA. Yes, I agree with Hege the no-clean makes PCB look pretty dirty however the soldering looks good and shinny. To wash out RMA flux, I may need chemicl cleaning, am I right? Currently, we use DI water to clean water soluble flux.

Best regards

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#63220

Water Soluble Flux | 1 December, 2010

Hegemon,

Thank you for the acknowledgment.

Jacki,

There are 3 rosin flux categories:

R – Pure rosin (no cleaning required) RMA – Rosin mildly activated (can be used without cleaning in non critical applications) RA – Rosin highly activated (due to the high activity level cleaning is advised)

Although I personally consider rosin fluxes old technology, if for whatever reason you have to use them and need to clean you have two options:

1) Solvent based cleaning chemicals

2) Water based cleaning a) Pre rinse with rosin saponifier in DI water b) Final rinse in DI water

Patrick

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#63224

Water Soluble Flux | 2 December, 2010

Hi Patrick

Thanks for your advice. Since bothering you, I wanna to ask one question," why is the water soluble solder not commomn in the market"?

Warmly regards

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#63228

Water Soluble Flux | 2 December, 2010

Hi Jacki,

Water soluble flux was for the majority used in the USA in the 80’s and 90’s under the motto “flux your problems away” (water soluble fluxes are very active). Water soluble fluxes have never been popular in the rest of the world. The main reasons why the use of water soluble fluxes is fading are:

A) Boards are a lot denser now then in the 80’s and 90’s so it gets more difficult to clean the boards effectively. And since water soluble flux residues are very corrosive when left on the board the reliability of the assembly is compromised.

B) Using water soluble flux requires cleaning equipment which is expensive to purchase and maintain.

C) When cleaning the boards there are many components that can’t go trough the wash cycle so they have to be manually assembled post cleaning.

D) From an environmental standpoint cleaning produces hazardous waste.

No-Clean/No-Residue flux has become very popular because A, B, C and D are totally eliminated making the overall process a lot more economic.

In your post you made it very clear that you believe that No-Clean fluxes compromise board cosmetics. This is simply because you used the wrong No-Clean flux.

Do a Google search for No-Residue flux to learn more.

I hope this makes things clearer for you.

Patrick

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#63229

Water Soluble Flux | 3 December, 2010

> Dear all Can any1 explain me about the variuos > types flux and their cleaning procedure? I have > confusion in claen,non-clean,RMA, and water > soluble. > > Thanks in advance.

http://shanelo.co.za/Design,%20process%20and%20reliability.htm

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#63230

Water Soluble Flux | 3 December, 2010

Thank Patrick

Very appreciated for your sharing.

Warmly regards

Jacki

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