EEVblog Electronics Community Forum
Products => Other Equipment & Products => Topic started by: John_ITIC on October 19, 2015, 11:09:10 pm
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I would be interested in purchasing an ultrasonic cleaner that absolutely removes all traces of flux residue off of my PCBs. I have found that at 5 Gigabit/second signaling rate, flux residue has a negative impact on signal integrity. Cleaning with flux remover, isopropyl alcohol and tooth brush improved the SI but I can still see under microscope that there are still traces of flux residue between vital IC pins. My USB 3.0 protocol analyzer showed packet error count go down from 1000 to 100 after the manual cleaning. It is very hard to get to the pins in question so I'm looking for "the best" solution (not necessarily the cheapest solution).
I have gone through earlier threads regarding ultrasonic cleaners but have not been able to figure out which one to get. My board is 120x100 mm so I don't need a large unit. I want a unit that works with IPA and that does not damage ICs via too much power.
Any recommendations? Links to relevant reviews etc. ?
Thanks.
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Most inexpensive (ebay) ultrasonic cleaners seem to work just fine in my experience. They have stainless steel basins, so no issues with IPA.
More importantly you'll need to determine if the flux you have on the boards is water or IPA soluble - some of the no clean fluxes can be an issue to dissolve. I presume these are hand/home assembled boards?
I'd also suggest a source of compressed air to then blow-dry the boards after their wash.
cheers,
george.
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IPA or any other flammable liquid is NOT recommended. The ultrasonic action can ignite.
There are specific detergents for PCB cleaning from Alconox and others.
Only consider units with frequency sweeping the reduces standing waves. Not only does that clean more effectively, it prevents damage to the PCB. It is possible to make very small scale damage to semi-conductors so the power and time should be considered.
There is a lot of subtlety in the process....temperature, power, frequency, detergents, etc. You should heat the system and de-gas each day and after adding fluid.
I used a single system with detergent followed by an aux tank with DI water. The PCBs were completely resudue free and it was easy.
Sent from my SAMSUNG-SM-G890A using Tapatalk
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Yes, these are hand-assembled / reflow assembled prototype boards. I'm using various fluxes for various use:
1) Sticky rosin-based flux for BGA reballing (Zephyrtronics). Very gunky stuff. Cleans up well with regular flux remover.
2) MG Chemicals no-clean 8341 flux paste. Not actually using but has a tube.
3) Leaded, no-clean MG chemicals 4860p, solder paste. For general board reflow.
4) Amtech NC-559-ASM flux paste, for BGA reflow (rework).
I also have a no-clean flux pen, not sure what it is but use it for general hand soldering. "Water soluble".
Regarding damage due to ultrasonic cleaning; is there any scientific study made on this? I have heard such rumors but not actually seen any proof of damage. Various YouTube videos say such IC damage is a myth.
Are there any entry-level professional units with the mentioned frequency sweep functionality, that are intended for PCB cleaning? I suppose jewelry units may work but may have side-effects such as component damage...
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This reminds me of something silly I did once.
I got an ultrasonic cleaner made for jewlery and decided to use it to clean some PCBs. Distilled water seemed to work well, and it had a stainless lining, so I decided to try something stronger. So i load it up with acetone (you see where this is going) and turned it on.
I came back a few hours later and reached for it to open the lid and the thing was basically taffy. my fingers poked through the lid like it was soft rubber. As you can guess, the ultrasonic vibrations atomized the acetone so that it infused into every plastic part of the machine. It was actually kind of odd. It wasn't pure ABS or it would have disolved into a mush pile, it more became like soft latex or something so there was some component of the plastic left with very different properties.
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As for scientific evidence...I am not sure. It sounds plausible and I don't have the resources to truly understand or test the long term effects of ultrasonic cleaning. Shortly after using the ultrasonic process, we had an unusually large number of failures that we could not figure out. I stopped using the ultrasonic cleaner and by chance the circuits were totally re-designed at the same time. I never went back to look for the origin of the problem which could have been any number of things. I won't blame the ultrasonic since I have no actionable data. If I felt the need to go back to it, I would allocate some time to make sure I was not creating a long term reliability problem from mechanically stressing the brittle materials IC are made from. One thing for sure is that aqueous ultrasonic cleaning is a molecularly violent process. A LOT of energy is focused on a very small area. It was a short lived experiment that was abandoned without a final conclusion.
I use the Crest 2600D for most stuff. It has been reliable and primarily used on small machined parts as part of the surface prep for plating. Not too expensive, heater, de-gas, varbiable power, digital timer. I don't know of any off the shelf unit that is specifically for PCB's.
http://www.ebay.com/itm/NEW-Crest-CP2600D-27-Liters-Benchtop-Ultrasonic-Cleaner-Heat-Timer-Degas-/121579544579?hash=item1c4eb4a003:m:mVTmLkYMSrHTEWd4Hnz2b1Q (http://www.ebay.com/itm/NEW-Crest-CP2600D-27-Liters-Benchtop-Ultrasonic-Cleaner-Heat-Timer-Degas-/121579544579?hash=item1c4eb4a003:m:mVTmLkYMSrHTEWd4Hnz2b1Q)
I used a few of the detergents from Alconox http://www.alconox.com/ (http://www.alconox.com/) and they seemed to do a great job. Hot DI water rinse is usually needed.
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The ultrasonic vibrations atomized the acetone so that it infused into every plastic part of the machine. It was actually kind of odd. It wasn't pure ABS or it would have disolved into a mush pile, it more became like soft latex or something so there was some component of the plastic left with very different properties.
That's amazing. :o Must have been quite surprising, too! :D
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Crest Ultrasonic Cleaners are the go to brand in the industry. Branson EC (Electronic Cleaner Concentrated
Cleaning Formula) is the detergent designed for cleaning PCBs (flux, rosin etc).
It's a good idea to get the tray with it, you need to suspend your PCBs in the middle of the cleaner not resting on the bottom.
You use distilled water and a tiny amount of Branson EC. Then flush with clean distilled water or IPA if you want to speed up drying time and/or displace water under components prior to drying.
A heated ultrasonic cleaner gives best results and you should avoid ones that have complex controls as all you need to do is turn it on, set the temp, monitor the time and perhaps flip your pcb half way through. A cooking timing or your smart phone etc means you can leave it unattended in the next room and not worry about noise or chemical issues and just come back to it when it's finished.
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I have had excellent results cleaning PCBs with Electrolube Safewash SWAS, both manually and in a ultrasonic cleaner. Best of all it's biodegradable and if diluted sufficiently can be tipped down the sink (read the MSDS).
http://www.electrolube.com/products/cleaning/swas/safewash_range_-_aqueous_cleaning/ (http://www.electrolube.com/products/cleaning/swas/safewash_range_-_aqueous_cleaning/)
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It's a good idea to get the tray with it, you need to suspend your PCBs in the middle of the cleaner not resting on the bottom.
Very true. For mechanical parts I have a wire basket. The goal is that the parts to be cleaned should be touching only the fluid as much as possible. I made a wire hanger that allowed me to hang a number of PCB's and dip them in the solution where they are suspended right in the middle.
Heat, in my opinion, is critical. The effectiveness of the process diminishes rapidly in cool water. Do not discount the benefit of the de-gas cycle either. It works to get rid of the tiny bubbles that are in suspension. The bubbles are too small to rise to the surface on their own and the de-gas cycle essentially pulses the transducers which causes the small bubbles to combine and rise out of the solution. The 'denser' fluid has a better effectiveness since the bubbles will stick to the surface and isolate that area from any ultrasonic action. Some people think that when you dip the part into the solution, it will get wet. That is not true. If the parts enters quickly, the cavitation will create bubbles that stick to the dirty surfaces and stay there during the cleaning cycle. The areas where the bubbles were will be untouched. Gently place the parts in the tank and gently remove them. Good detergents help this as well.
My thinking was that if all the parameters are optimized, it will reduce the cycle time, improve the end result, and minimize risk of damage to the the PCB/components.
Note on disposal: Even if your detergent is biodegradable, the stuff you cleaned off the PCB is probably not.
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Ok, Crest it is. Branson EC seems easiest to find in the U.S. So if I get the below equipment & solution, I would be good to go?
http://www.ebay.com/itm/Crest-0-5-Gal-Benchtop-Ultrasonic-Cleaner-w-Heater-and-Mechanical-Timer-CP200HT-/181079242250?hash=item2a2929f60a:m:mdH2iiZCWuvulWDvmfXHKjQ (http://www.ebay.com/itm/Crest-0-5-Gal-Benchtop-Ultrasonic-Cleaner-w-Heater-and-Mechanical-Timer-CP200HT-/181079242250?hash=item2a2929f60a:m:mdH2iiZCWuvulWDvmfXHKjQ)
http://www.all-spec.com/products/635-028.html?gclid=CPfd_bCd0sgCFQiNaQod5V8LrA (http://www.all-spec.com/products/635-028.html?gclid=CPfd_bCd0sgCFQiNaQod5V8LrA)
Thanks,
/John.
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Think about ordering one with the wire tray as well.
Make sure what you're cleaning fits in the tray at least at a 45 degree angle comfortably and will be totally submerged. You need to think of future needs as well. The 45 degrees helps get the agitating action get up around components.
If you buy the gallon of detergent its about 25% cheaper but you need to work it out yourself (if you need that much).
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When you have something lIke the ti hdc1008 ( with an hole in the bottom) how would you clean that?
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When you have something like the ti hdc1008 ( with an hole in the bottom) how would you clean that?
BGA with an ultrasonic cleaner setup for cleaning electronics as well. If it's sensitive to cleaning then you best read up or contact the manufacturer. You are submerging at temperature and it's a mildly abrasive cleaning method (results depend how long you clean). So writing on labels, adhesives and rubber and that kind of material can be affected especially if you leave it in too long. Some labels may wear straight away, the ones on components are normally hard wearing though.
If you read the Branson EC specs it says it can slightly tarnish polished aluminum.
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I use acetone, works better than ipa, and unlike ipa, there is no law prohibiting its use in any concentration.
There are laws prohibiting IPA where you are? I can understand methanol having some restrictions, but IPA is not really more dangerous than a lot of household things.
In any case, you can turn any percentage IPA into 100% IPA just by adding salt. salt water and isopropyl are not miscible, so when you add a bunch of salt to a water IPA mix, it seperates out into a salt water and pure alcohol layer, you then just siphon off the pure alcohol layer.
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The "air quality" rules in Southern California are imbecilic. Volatile Organic Chemicals are the enemy, and you can't have them! Except for acetone, that doesn't count because... um... because we need it to do our nails. Please don't tell us that watering down cleaners will lead to more waste and pollution, that's somebody else's problem.
Acetone is not great for PCB cleaning. Not only is the smell overpowering, but it attacks ABS resins and destroys switches and capacitor seals.
Asahiklin AK-225 was close to ideal, and you could buy it until last January. Some of us have stockpiles...
Now that it is no longer available, there are new mixtures on the market that claim to dissolve stubborn no-clean fluxes. Reading the MSDS for cleaners can be interesting (remember that ingredients judged non-hazardous do not need to be listed). Many of the "heavy duty" cleaners contain DuPont's Vertrel, a series of decafluoropentanes. Some use even more exotic solvents, like Honeywell's "Solstice", a chlorofluoroalkene that is evidently not yet banned.
http://www.all-spec.com/products/acl8620.html (http://www.all-spec.com/products/acl8620.html)
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Acetone? WTF? Seriously?
That is a horrible solution.
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Acetone? WTF? Seriously?
That is a horrible solution.
I'm surprised at this. I have stored many pulled components in pure acetone to clean them up (no electrolytic caps, to be sure), and I have yet to break/melt anything. I actually came to suspect there was an unspoken rule that board-level electrical component plastics must be resistant to acetone. For a short exposure (not necessarily ultrasonic cleaning), I would have thought acetone would be far from a WTF-level of horrible.
I rarely bother to clean rosin residue, but I have noticed that acetone works much better on it (i.e. great) than alcohol. No cleans, different story.
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IPA will work with Rosin it just takes a while and it doesn't seem to dissolve off, it's more like it saturates very slowly with alcohol. So unless your scrubbing it, whats not been loosen off or washed away will stay in place, at least that is what I experienced when I tried it.
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http://www.ebay.com/itm/Crest-0-5-Gal-Benchtop-Ultrasonic-Cleaner-w-Heater-and-Mechanical-Timer-CP200HT-/181079242250?hash=item2a2929f60a:m:mdH2iiZCWuvulWDvmfXHKjQ (http://www.ebay.com/itm/Crest-0-5-Gal-Benchtop-Ultrasonic-Cleaner-w-Heater-and-Mechanical-Timer-CP200HT-/181079242250?hash=item2a2929f60a:m:mdH2iiZCWuvulWDvmfXHKjQ)
http://www.all-spec.com/products/635-028.html?gclid=CPfd_bCd0sgCFQiNaQod5V8LrA (http://www.all-spec.com/products/635-028.html?gclid=CPfd_bCd0sgCFQiNaQod5V8LrA)
/John.
Thanks Everyone, I just placed an order for the above equipment. For a while, I was eying the cheap Ebay clones but eventually figured I'd buy a unit that will last some 10 years. Also, It would be silly to put my $3,000 prototype PCB into the cheap $50 cleaner, trying to save a few bucks...
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Hello,
Saving nature and reusing an old thread.
Paintbrush and IPA work just fine for surface cleaning, but would like to have deeper cleaning using ultrasonic. There are several liquids to choose from, but all the products I have found requires rinsing with water. Anyone using alcoholic based cleaner with ultrasonic? (something that is meant to use use that way and is non-flammable)
A
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I would not put solvent into an ultrasonic cleaner without a gas flood box to operate it in, if you have a friend that welds aerospace titanium he might have a chamber you can use
That is considered mad dangerous. What you can do though, that is much less dangerous, so long you work outside, is put the alcohol in a bag (limited amount), then put the board in the bag. Not sure if you can use a ESD bag. It will hold up for a little while and if it leaks the alcohol will immediatly go into the water and so long you have alot of water, the mixture is never flammable, so you only need to manage small possible vapor problems... but if you poured 1/2 a gallon of ipa into a stock ultrasonic I would be real scared of that setup.. I highly recommend investing in a flux cleaning solution that is not flammable for this job.
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Hello,
Saving nature and reusing an old thread.
Paintbrush and IPA work just fine for surface cleaning, but would like to have deeper cleaning using ultrasonic. There are several liquids to choose from, but all the products I have found requires rinsing with water. Anyone using alcoholic based cleaner with ultrasonic? (something that is meant to use use that way and is non-flammable)
A
I use an ultrasonic cleaning solution then afterwards use compressed air on the PCB. If the surface finish is not acceptable, spray down with inexpensive brake cleaner.
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"SteveyG"
The cleaner you are using is meant to be rinsed after ultrasonic processing? All the ultrasonic cleaners I have found are like that. If there is a cleaner that does not require anything but one-step ultrasonic processing I would be appreciated to know what is that product.
A
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Hi,
in this thread was mentioned, that ultrasonic cleaning can destroy electronic components. I did not believe this, until today.
I am currently repairing an Instrument from a seller from Israel, which was extremely dirty inside. (No complain about the seller, I was aware about the state of this instrument)
The dirt (desert sand?) was extremely hard to remove, so I used an ultrasonic cleaner. For some of the modules I needed three cleanings from about 20 minutes to remove all the mess.
Now everything is clean, BUT two modules, that worked before the cleaning, have stopped working now.
The reasons are 9 defective RF Transistors (2N5179) which have an interrupted collector now. |O
So, be careful, not every semiconductor likes ultrasonic cleaning.
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Fyi I would not be surprised if those isreali instruments were run over by tanks before sale.
I think also if a transistor has been overloaded alot and stuff like that, there is strain in there that will make it more susceptible to ultrasonic damage.
I ultrasoniced an amplifier I got from Israel that was mad filthy but it was OK afterwards, but it is a lower frequency type (MHz). Not sure I wanna think about what kinda nasty shit might accumulate in old IDF equipment anyway
And are you sure the transistors were functioning properly? If its really dirty they coulda been shorted out by grime coupling small signals making something kinda work
Mmm but the bigger problem I have with ultrasonic is that sometimes it rubs text off things. I never had damage but the text being removed is a serious hindrance, and you should probobly make a diagram of what part was where before engaging in heavy cleaning, that can RUIN your day. I use simple green with a brush to do boards that I am worried about text. The problem is usuaully/always metal can transistors. They used to like ink it back in the day. Transformer bodies too. And of course if there was seal failures in the parts due to strain and liquid got in there..
did you try baking the board? After ultrasonic cleaning I always do a clean water dip (preferrably a clean water ultrasonic for a min, requires tank switch), to help dissociate all the contaminates into the clean water under high preference for osmotic flow, then bake at a low temp (40C+). Just make sure you dont trust any oven ever, I think I damaged foil caps that way. To get rid of all the humidity you would need to do the 'pre soldering' procedure you do with damp SMD parts on the whole PCB.
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Not sure I wanna think about what kinda nasty shit might accumulate in old IDF equipment anyway
Matzo balls?
I have seen some heavily beat equipment for sale from Israel, but it doesn't appear to be treated any worse than ex-military gear that was used in the field from other countries. The difference may be the legal allowances (or chutzpah) placing the equipment for export sale. Many other countries do not allow export of mil surplus.
I use simple green with a brush to do boards that I am worried about text. The problem is usuaully/always metal can transistors. They used to like ink it back in the day. Transformer bodies too. And of course if there was seal failures in the parts due to strain and liquid got in there
Simple Green is an aggressive cleaner containing butyl ethers, similar to Goof-Off or graffiti remover. I'm not sure it belongs in an electronics shop.
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maybe it used to contain butyl ethers, the formula was changed since then, I think since 2003
https://en.wikipedia.org/wiki/Ethoxylation#Alcohol_ethoxylates
Anyway, its great stuff, if you spray down a PCB with a squirt bottle and brush it with a bamboo bristle brush, its enough to rinse it with hot water to easily clean a 17 inch chassis in a kitchen sink.
Metal cans that are labeled, only some types of labeling, on the older parts (germanium age), the ink is sensitive to the modern formula of simple green, if its hot, and used for a long time, but usually the text is in BAD SHAPE to begin with, whenever I see that initial quality of labeling I try to scribe over it with a engraving tool.
I have not seen any damage to silk screen, plastic parts or modern metal parts from a short ultrasonic clean with it. It also works on tobbaco pipe condensate, leaked capacitor goo and chemically weakened flux (like flux that gets puffy from solvent) and weakened conformal coat also comes off. Keep in mind its a concentrate and used very dilute.
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Old thread, but no point making a new one.
I trust Chemtools here in Sydney, but anything else worth considering?
https://www.chemtools.com.au/product/electrical-electronics/cleaners-flux-removers/pcb-flux-remover/ (https://www.chemtools.com.au/product/electrical-electronics/cleaners-flux-removers/pcb-flux-remover/)
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If you want a water-based, non-ionic cleaner, cellosolves (https://en.wikipedia.org/wiki/Glycol_ethers) are hard to beat IMHO.
As I have mentioned many times, acrylic floor strippers and Kester water-based flux cleaners are based on them. By far the most common is butyl cellosolve, which has a distinctive order. A final concentration of about 10% butyl cellosolve works. Even a lower concentration works. I would not recommend going to higher concentrations and definitely not neat. They will remove cured enamel when neat.
Both Kester and floor stipper contain a little ethanol amine or similar as a "saponifier."
I noticed recently that very thin gold flashing may also be removed. I was cleaning a solderable SparkFun protoboard and after 2 minutes, the gold looked a bit like nickel. Thirty seconds may be enough for flux.
Boards come out remarkably clean and hydrophobic. I rinse briefly under a sink faucet, then once in the ultrasonic with distilled or equivalent water and blow dry.
EDIT: I use ZEP brand heavy duty floor stripper. ZEP is an international brand, but I was told by a chemist there a few years that it is not sold by that brand in Australia. It's about 30% cellosolve, so I dilute 1:3 or 1:4 (1 part to total parts).
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hey yeah also I re read the thread, 20 minutes (3 times!) is ALOT. A few things I saw showed that about 5 minutes is the end of the safe zone for IC!!!
I suggest that you do a soak. Ultrasonic should be fast. If you think you need 20 minutes in a cleaner, try a long soak followed up by say a 1-2 minute clean.
The soap has its own chemical action that is probboly not effected by the sonic energy, that needs time to work too. Jewlery workers often only need 10-15 seconds to get their stuff clean. There is imo a good chance that if you need the whole 20 minutes, a big portion of that time might just be what the soap needs to infiltrate the grime natrually.
And heat too, warm soak. it makes a world of difference with soap if you get it warm.
and despite all the magic properties, its not like it gets rid of the utility of scrubbing. if you mechanically disturb grime with a brush, it will come off much faster.
Where the ultrasonic is good is that it can do the small spots that you can't hit, like under chips, in crevaces, etc. And even so, if you get the right tools (i.e. a soft bristle brush of the correct size, bottle brushes) so you can do a bit of poking under chips and stuff, to kinda disturb the contamination, after the soak but before the ultrasound, it will drastically reduce the time in the cleaner, because you will mechanically push out and break up large chunks that take a while to get 'disintegrated' by the energy without help. For instance, soft bristle brush to poke in under a IC, bottle brush around a potentiometer, etc.
Also the new concern I have with long term exposure is that it could do damage to the plating inside of carbon pots (they have a substrate, and a coating that is resistive. if you leave them in for too long (too lazy to disassemble and scrub (real gentle)/soak a bit, it can remove the coating that does the work, especially if its degraded).
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Old thread, but no point making a new one.
I trust Chemtools here in Sydney, but anything else worth considering?
https://www.chemtools.com.au/product/electrical-electronics/cleaners-flux-removers/pcb-flux-remover/ (https://www.chemtools.com.au/product/electrical-electronics/cleaners-flux-removers/pcb-flux-remover/)
I've ordered 5L of this stuff, that at least gives me one option for PCB's.
Can you re-use it? I assume maybe yes depending on conditions?
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bulk cleaner (transport) can be a hidden cost with the distances between cities in Australia. I prefer to use a concentrate and mix
with deionised water when I need it.
Another trick is to put the object to be cleaned in it's own (thick/heavy) resealable plastic bag with the cleaning solution and put that into the ultrasonic cleaner filled with water (saves on cleaning solution)
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I've ordered 5L of this stuff, that at least gives me one option for PCB's.
Can you re-use it? I assume maybe yes depending on conditions?
The functional components of that cleaner are similar to those in Kester flux removers and floor stripper I use (attached).
Dipropylene glycol monomethyl ether is a glycol ether and a great solvent. Ethanolamine is the same in each. The sulfonic acid is an anionic surfactant. It is probable both Kester and floor stripper have something like that too. I am a little surprised it is used presumably neat as the concentration of the glycol ether is about 2 to 3 times the working concentration of the other two.
As for reuse, I do reuse mine for a few single boards, but toss it when it shows precipitates. One could probably filter it, but floor stripper is cheap. I don't do production. The faucet rinse is pretty effective at removing dirty cleaner.