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Has anyone heard of a no clean paste that can be cleaned in straight DI water ?

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I'm looking for a No Clean SAC 305 Solder Paste that can be ... - Jan 26, 2018 by Clockwatcher  

#79658

Has anyone heard of a no clean paste that can be cleaned in straight DI water ? | 26 January, 2018

I'm looking for a No Clean SAC 305 Solder Paste that can be run through our inline wash. No chemicals just DI water.

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#79659

Has anyone heard of a no clean paste that can be cleaned in straight DI water ? | 26 January, 2018

Sorry to disappoint. No-Clean fluxes are resin-based. They are not soluble in water. Water soluble fluxes are by nature Organic Acid and are soluble in water AND must be cleaned within a short period after reflow as they remain conductive and corrosive.

MikeKonrad

konrad@aqueoustech.com

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dwl

#79661

Has anyone heard of a no clean paste that can be cleaned in straight DI water ? | 26 January, 2018

Amtech LF4300 is exactly what your looking for.

http://www.inventecusa.com/assets/lf-4300.pdf

Insert standard "I receive no benefit nor compensation from the aforementioned company"

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#79668

Has anyone heard of a no clean paste that can be cleaned in straight DI water ? | 29 January, 2018

I still find it weird when people clean "NO clean" - it defeats the purpose.

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#79672

Has anyone heard of a no clean paste that can be cleaned in straight DI water ? | 30 January, 2018

I believe the correct statement (I've been told) is "the process is no clean". The solder paste is "low residue". As a CM, in the past we had customers that insisted on a wash after soldering. We used DI water with a saponifier which had mixed results. Sometimes you can't convince someone that the low residue flux remnants are benign and do not affect the long term reliability of the product, they still want shiny and clean. If we could go back to the TRI 1,1,1 and liquid Freon cleaning era.....that would be great, oh except for that environmental thing.

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#79673

Has anyone heard of a no clean paste that can be cleaned in straight DI water ? | 30 January, 2018

If you go even further, the flux residue actually isolates the joints from the surrounding atmosphere, so it is actually supposed to be there. Adding a step in your process that is obsolete, doesn't comply very good with the whole lean concept. I don't even want to go into defects caused by cleaning.

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#79675

Has anyone heard of a no clean paste that can be cleaned in straight DI water ? | 30 January, 2018

This is one of the most common questions I get asked. Why clean no-clean flux. It was stated earlier that no-clean residues are benign. This may or may not be accurate. It depends on several factors including the reflow process. In a perfect world, the low-level flux residues are benign. In a less-than-perfect world, they may not be. There may be un-encapaulated flux activators or other ionic residues left behind if the reflow profile was not ideal for the specific flux type and volume.

More importantly, when flux residues are not removed, nothing is removed. We should not consider cleaning assemblies a "de-fluxing process" rather we should consider it a "cleaning process". When we do not remove flux, we allow all residue species to remain on the assembly. These residues include board fabrication residues, component fabrication residues, assembly residues (including flux) and human contact residues. Modern circuit assemblies are less residue tolerant than yesterday's assemblies were. Contamination in its totality leads to electro-chemical migration failures, not just flux residues.

A few months ago, I recorded a short video (non commercial) explaining these issues. Perhaps it will be helpful. Here's a link: http://www.aqueoustech.com/to-clean-or-not-to-clean

I hope this helps.

Mike Konrad konrad@aqueoustech.com

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#79678

Has anyone heard of a no clean paste that can be cleaned in straight DI water ? | 31 January, 2018

Michael What you say is not a reason for washing. It is a reason to not use Can't Clean solder paste. Although I guess if they use the real name they wouldn't sell as much as they do by calling it No Clean.

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#79679

Has anyone heard of a no clean paste that can be cleaned in straight DI water ? | 31 January, 2018

"...electro-chemical migration failures..." Come on Michael, You are totally selling it here.

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#79691

Has anyone heard of a no clean paste that can be cleaned in straight DI water ? | 1 February, 2018

Your right, he is "selling it". Or I should say he is not selling no-clean solder paste.

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#79694

Has anyone heard of a no clean paste that can be cleaned in straight DI water ? | 1 February, 2018

... >"...electro-chemical migration failures..." Come on Michael, You are totally selling it here.<

Evtimov: What do you mean? Are you saying that electro-chemical migration failures like tin whiskers and dendrites are not a concern? Are you one of those ECM deniers?

Look here:

* NASA "Metal "Dendrites" are NOT the Same as Metal "Whiskers"" [https://nepp.nasa.gov/whisker/dendrite/index.html]

* NASA "Basic Information Regarding Tin Whiskers" [https://nepp.nasa.gov/Whisker/background/index.htm]

Attachments:

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#79696

Has anyone heard of a no clean paste that can be cleaned in straight DI water ? | 1 February, 2018

Thank you Davef! That was overreaction to the seller - I don't deny anything.

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#79697

Has anyone heard of a no clean paste that can be cleaned in straight DI water ? | 1 February, 2018

I've known Mike Konrad for over 20 years. I like him. He is knowledgeable and giving of that knowledge. I no issues with what he said in his vid.

We should not to get overly twitchy when someone, sales-type or not, makes an effort to help us do our jobs.

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#79698

Has anyone heard of a no clean paste that can be cleaned in straight DI water ? | 1 February, 2018

Not to be repetitious, I just don't remember if this has been said or not, I'm old, give me a break.

Some people have found that DI water is too thick to properly remove flux residue under low stand-off components.

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#79700

Has anyone heard of a no clean paste that can be cleaned in straight DI water ? | 1 February, 2018

Thanks for the kind words Dave. At no point in my reply was I trying to sell anything. I apologize to anyone who believes otherwise. I agree with the poster, if assemblies are going to be cleaned, consider a flux designed to be cleaned. While this is good advise, there are many reasons assemblers give to reflow with no-clean flux, even if they are cleaning it. The primary reason I hear is the desire to run one common flux type and clean just the assemblies that require cleaning. This action adds efficiencies within the assembly process. Ironically, most fluxes cleaned today are "no-clean". This would make more sense if we referred to "no-clean" fluxes as "low residue" fluxes. The reality is many assemblies can tolerate low residues and do not require post-reflow cleaning. For those assemblies that are less residue tolerant, cleaning is an option.

Finally, contamination related ECM is not an overstatement. It is a reality which affects our industry. Unfortunately, carpenters see the world as a sea of nails and, perhaps, cleaning equipment and chemical manufacturers see the world as a sea of harmful residues. I am reminded, while I see this everyday, others do not. The reality is not every assembly requires cleaning. There are many assemblies that are highly reliable without the added step of cleaning. There are also others, without the removal of fabrication and assembly residues, may be subject to electro-technical migration issues including dendritic growth and parasitic leakage.

Ok... I will try to sneak away now without creating any more drama ;-)

Mike Konrad

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#79703

Has anyone heard of a no clean paste that can be cleaned in straight DI water ? | 2 February, 2018

Mike,

sorry for being aggressive on you! After all we are on this forum to help each other. Please accept my apology! Great post by the way!

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#79707

Has anyone heard of a no clean paste that can be cleaned in straight DI water ? | 2 February, 2018

Evtimov, no worries. I appreciate your knowledge and contributions over the years.

Mike Konrad

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