Flux Removal? Ultrasonic Bath?

[ogden]

One company I worked for put production boards in a dishwasher to clean off flux.

With some preconditions: 1) water-soluble flux 2) no BGAs no flip-chips or alike 3) deionized water for rinse or even washing, optionally 2nd rinse using alcohol

[David Hess]

One company I worked for put production boards in a dishwasher to clean off flux.

With some preconditions: 1) water-soluble flux 2) no BGAs no flip-chips or alike 3) deionized water for rinse or even washing, optionally 2nd rinse using alcohol

I have seen boards put into a dishwasher with deionized water before assembly to lower leakage and remove contaminates which interfere with soldering.

[Gibson486]

Be careful what you put in that ultrasonic bath. Research it before you do it. I have seen it suggested many times...but do not put IPA in there. That is actually a hazard.

[radeohedca]

Believe it or not, we use a dishwasher at work to clean boards... it was bought specifically for this purpose. It works very well for the flux used in newer ROHS lead free solders. They come out sparkling clean and the dry cycle ensures there's no residual water.

[tooki]

What flux type? Lead-free solders are available with all the major types of fluxes, including rosin, no-clean, and water-soluble.

[wraper]

What flux type? Lead-free solders are available with all the major types of fluxes, including rosin, no-clean, and water-soluble.

No-clean is not a type of flux in such context. No-clean can be rosin based, synthetic or even water soluble. All it means it is marketed by manufacturer as flux that can be left on PCB.

[tooki]

What flux type? Lead-free solders are available with all the major types of fluxes, including rosin, no-clean, and water-soluble.

No-clean is not a type of flux in such context. No-clean can be rosin based, synthetic or even water soluble. All it means it is marketed by manufacturer as flux that can be left on PCB.

Only if you dissect the term literally, which is not wise — That's what smart alecks do when they want to show how smart they are, but in fact are just being turds.

In the solder industry, solders are practically always broadly divided into rosin, no-clean, and water-soluble. Moreover, I said "all the major types of fluxes, including rosin, no-clean, and water-soluble", meaning it was not an exhaustive list, leaving room for things like water-soluble no-clean.

Now, I actually kinda hate the term "no-clean" since it can indeed mean damned near any formulation, it not being a strictly defined term. Nonetheless, the overwhelming majority of solders and fluxes fall into those three categories, whose basic meaning is this:
Rosin: a flux with a high rosin content, where rosin is the dominant active ingredient
Water-soluble: water-soluble organic acids, with the expectation of cleaning
No-clean: low amounts of harmless residues


And your entire argument/lecture added exactly what to the discussion anyway? My question to radeohedca remains: what type of flux is it?

[wraper]

In the solder industry, solders are practically always broadly divided into rosin, no-clean, and water-soluble.

What solder industry you are talking about? And how you distinguish rosin from no-clean? Rosin flux on the other hand might need cleaning for active types. Not all fluxes which must be washed are water-soluble too. Your way of describing flux types is a complete ambiguous mess.

[wraper]

[tooki]

In the solder industry, solders are practically always broadly divided into rosin, no-clean, and water-soluble.

What solder industry you are talking about?

"Solder industry" is English for "the industry that manufactures soldering consumables (solders and fluxes)".

And how you distinguish rosin from no-clean?

Read my previous reply.

Rosin flux on the other hand might need cleaning for active types.

Correct.

Not all fluxes which must be washed are water-soluble too.

I didn't say that only water-soluble fluxes must be washed.

Your way of describing flux types is a complete ambiguous mess.

It's not "my" way. It's the way the industry broadly categorizes them.

Look at the product names of practically all fluxes/solders: almost all contain EITHER "rosin", "no-clean", OR "water soluble". That tells you what broad category it's in. Then the specs will tell you the precise flux classification.

[wraper]

In the solder industry, solders are practically always broadly divided into rosin, no-clean, and water-soluble.

And they certainly don't describe fluxes this way.

Read my previous reply.

Huh? It's meaningless. You separate rosin and no-clean as different types. They are not, they describe different properties and overlap a lot.

It's the way the industry broadly categorizes them.

Didn't notice this in datasheets at all.

[wraper]

Say this one https://www.kester.com/DesktopModules/Bring2mind/DMX/Download.aspx?EntryId=3558&PortalId=0&DownloadMethod=attachment
It's rosin mildly activated (ROM0) no-clean flux. Almost everything that is non-corrosive and non-conductive is called no-clean these days.
Or this https://www.kester.com/DesktopModules/Bring2mind/DMX/Download.aspx?EntryId=31875&PortalId=0&DownloadMethod=attachment
Non diluted rosin flux with low activation, still called no-clean. It's not even mentioned that it's rosin, you need to look into ROL0 classification to see what it actually is.

[helius]

The flux and solder companies, like most industries, have multiple audiences they need to communicate with and advertise to. The engineers are going to want to see the IPC STD category and test results as this lets them know that the product is suitable for their reliability requirements. The managers who sign the purchase orders, on the other hand, want to know that what they're doing is in line with industry trends they read about in the trade press. "No-Clean" is a very easy concept to understand: you don't need a post-cleaning line. The details of the formulation would be lost on them anyway.

[tooki]

In the solder industry, solders are practically always broadly divided into rosin, no-clean, and water-soluble.

And they certainly don't describe fluxes this way.

Bullshit. They absolutely do:

Kester: https://www.kester.com/products/category/tacky-solder-flux
Type: No-Clean/Rosin/Water-Soluble

AIM: https://aimsolder.com/liquid-flux-and-paste-flux
Flux Type: No Clean/Rosin/Water Soluble

MG Chemicals: https://www.mgchemicals.com/category/soldering-supplies/soldering-flux/
"The flux comes in both liquid and paste formats, and in Rosin Activated (RA), No Clean (NC) and Water Soluble (WS) flux chemistries."

Chip-Quik: https://www.chipquik.com/store/index.php?cPath=300
No-Clean/RMA/no-clean water-washable/water-soluble

Elsold: https://www.tamura-elsold.de/datenblaetter/tacky_flux_en/TEG_TDS_EN_ELSOLD%20Tacky%20Flux.pdf
Flux Type: No clean/water soluble


Not every manufacturer applies the broad categories (or only uses them in body text), but they're widely understood throughout the industry.

As I already stated: the datasheets will always tell you the precise classification (and often more, since the formal classifications themselves don't tell you everything, either).

Read my previous reply.

Huh? It's meaningless. You separate rosin and no-clean as different types. They are not, they describe different properties and overlap a lot.

Of course there's overlap. But those terms explain the dominant characteristic, which I explained.

It's the way the industry broadly categorizes them.

Didn't notice this in datasheets at all.

Then you haven't read enough datasheets, or didn't pay attention.

[tooki]

Say this one https://www.kester.com/DesktopModules/Bring2mind/DMX/Download.aspx?EntryId=3558&PortalId=0&DownloadMethod=attachment
It's rosin mildly activated (ROM0) no-clean flux. Almost everything that is non-corrosive and non-conductive is called no-clean these days.
Or this https://www.kester.com/DesktopModules/Bring2mind/DMX/Download.aspx?EntryId=31875&PortalId=0&DownloadMethod=attachment
Non diluted rosin flux with low activation, still called no-clean. It's not even mentioned that it's rosin, you need to look into ROL0 classification to see what it actually is.

That's all correct, and none of that is in any way contradictory to anything I've said so far.

No-clean isn't a formal flux classification, as you've correctly identified and repeated over and over under the impression nobody else understands that. That's why you shouldn't be surprised that you find "traditional" classifications on no-clean fluxes: the classification tells you nothing about the amount of residue, which is, next to the inert nature of the residue, the biggest part of what makes a flux "no-clean".

[wraper]

Bullshit. They absolutely do:

Kester: https://www.kester.com/products/category/tacky-solder-flux
Type: No-Clean/Rosin/Water-Soluble

AIM: https://aimsolder.com/liquid-flux-and-paste-flux
Flux Type: No Clean/Rosin/Water Soluble

MG Chemicals: https://www.mgchemicals.com/category/soldering-supplies/soldering-flux/
"The flux comes in both liquid and paste formats, and in Rosin Activated (RA), No Clean (NC) and Water Soluble (WS) flux chemistries."

Chip-Quik: https://www.chipquik.com/store/index.php?cPath=300
No-Clean/RMA/no-clean water-washable/water-soluble

Elsold: https://www.tamura-elsold.de/datenblaetter/tacky_flux_en/TEG_TDS_EN_ELSOLD%20Tacky%20Flux.pdf
Flux Type: No clean/water soluble

Those are just quick filters. And selecting "Rosin" in most cases will show rare rosin fluxes which are not called no-clean.
EDIT: and under "Rosin" name usually hides some really old flux formulation.

Of course there's overlap. But those terms explain the dominant characteristic, which I explained.

What dominant characteristic there is for rosin vs no-clean rosin? What bugs me is that you separated rosin from no-clean as different types with no proper explanation. And so many people for years misunderstand this Rosin vs no-clean thing.

[tooki]

Bullshit. They absolutely do:

Kester: https://www.kester.com/products/category/tacky-solder-flux
Type: No-Clean/Rosin/Water-Soluble

AIM: https://aimsolder.com/liquid-flux-and-paste-flux
Flux Type: No Clean/Rosin/Water Soluble

MG Chemicals: https://www.mgchemicals.com/category/soldering-supplies/soldering-flux/
"The flux comes in both liquid and paste formats, and in Rosin Activated (RA), No Clean (NC) and Water Soluble (WS) flux chemistries."

Chip-Quik: https://www.chipquik.com/store/index.php?cPath=300
No-Clean/RMA/no-clean water-washable/water-soluble

Elsold: https://www.tamura-elsold.de/datenblaetter/tacky_flux_en/TEG_TDS_EN_ELSOLD%20Tacky%20Flux.pdf
Flux Type: No clean/water soluble

Those are just quick filters.

Yes, now you're starting to understand!
Nobody ever said they were formal, strictly defined classifications/standards.

And selecting "Rosin" in most cases will show rare rosin fluxes which are not called no-clean.
EDIT: and under "Rosin" name usually hides some really old flux formulation.

That's literally the point: they're not "hiding" it, "rosin" as a category is used to refer to traditional-style formulations, specifically to contrast with the newer formulations, which are almost entirely water-soluble or no-clean.

Of course there's overlap. But those terms explain the dominant characteristic, which I explained.

What dominant characteristic there is for rosin vs no-clean rosin? What bugs me is that you separated rosin from no-clean as different types with no proper explanation.

I take issue with you repeatedly blaming me for this terminology, when I am simply going by the industry-standard nomenclature. I am not calling them "rosin" vs "no-clean" because of not understanding the chemistry, I call them that because that's what the manufacturers (and the electronics industry at large) call them.


And I did give you a "proper explanation":

Now, I actually kinda hate the term "no-clean" since it can indeed mean damned near any formulation, it not being a strictly defined term. Nonetheless, the overwhelming majority of solders and fluxes fall into those three categories, whose basic meaning is this:
Rosin: a flux with a high rosin content, where rosin is the dominant active ingredient
Water-soluble: water-soluble organic acids, with the expectation of cleaning
No-clean: low amounts of harmless residues

And so many people for years misunderstand this Rosin vs no-clean thing.

Yes, so the confusion was not caused by my choice of words in this thread. I think it's more your personal frustration with the emergence of fluxes labeled as "no-clean" despite the fact that a) no-clean fluxes still need to be cleaned in some situations, and b) before "no-clean" fluxes came out, it was widely understood that rosin flux residues didn't need to be removed in most situations.

But good luck trying to convince the entire electronics industry to abandon the term "no-clean" in favor of the more accurate "non-corrosive, low-residue" just because the imprecision of the wording irritates you…   Wait till you find out that ROM is actually random-access, too, and that tomatoes and watermelons are actually berries!

[ogden]

It shall be noted that rework/hand-solder flux and solder-paste flux formulations differ. Engineers are usually fine with "no-clean" and "water-soluble" classification. Those who are responsible for process then read datasheets and IPC standards. Obviously it is good idea to use water soluble flux when washing is part of the process for some (absolute necessity) reason.

[NivagSwerdna]

This thread has developed in an interesting way.  To be clear on my original requirement though... this is absolutely not a rework context... it is a small manufacturing context, and currently hand soldered.  (In fact there are many components that are not easily reflowable)

[ogden]

For small amount of hand-soldered connections local cleaning is always better choice. Just bulk-buy cleaning solution and swabs, use flux that is easy to (hand)clean, test your process. When think about full washing also consider - if your components are not OK in reflow, then maybe they do not like (immersion in) water as well?

[edit] Saying rework solder I mean hand soldering as well. Edited previous post accordingly.

[helius]

Hand soldering for assembly and hand rework are similar in many ways, and some operators may use the same tools and materials for both. But as long as the components are fresh and shiny, you can often use less active fluxes for assembly, and lower temperatures, than you would for rework.

Metcal advertises its MFR workstations with different handpieces for assembly (tips fitting over a coil unit) or rework (cartridges). Since assembly is less demanding, but has a higher work cycle (more joints /hr?) the tip version has lower cost of ownership.

[ogden]

Metcal advertises its MFR workstations with different handpieces for assembly (tips fitting over a coil unit) or rework (cartridges). Since assembly is less demanding, but has a higher work cycle (more joints /hr?) the tip version has lower cost of ownership.

Right. Cartridges for rework is logical choice because rework most likely requires often change of the tips. Assembly must be optimized as much as possible meaning change of the tip shall be expected only when it is worn-out/unusable. Thus different types of irons.