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Tin Whiskers — Fact Or Fiction?
Posted by
timothy
on Sun Jun 15, 2008 02:49 PM
from the shave-before-dates dept.
from the shave-before-dates dept.
bLanark writes "Some time ago, most electronics were soldered with old-fashioned lead solder, which has been tried and tested for decades. In 2006, the EU banned lead in solder, and so most manufacturers switched to a lead-free solder. Most made the switch in advance, I guess due to shelf-life of products and ironing out problems working with the new material. Lead is added to solder as it melts at low temperature, but also, it prevents the solder from growing 'whiskers' — crystalline limbs of metal. The effect of whiskers on soldered equipment would include random short-circuits and strange RF-effects. Whiskers can grow fairly quickly and become quite long. Robert Cringley wrote this up this some time ago, but it seems that the world has not been taking notice. I guess cars (probably around 30 processors in a modern car) and almost every appliance would be liable to fail sooner than expected due to tin whiskers. Note that accelerated life-expectancy tests can't simulate the passing of time for whiskers to grow. I've googled, and there is plenty of research into the effects of tin whiskers. I should point out that the Wikipedia page linked to above states that tin whisker problems 'are negligible in modern alloys,' but can we trust Wikipedia? So: was the tin whisker problem overhyped, was it an initial problem that has been solved in the few years since lead-free solder came into use, or is it affecting anyone already?"
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Will my tin foil hats (Score:5, Funny)
Re:Will my tin foil hats (Score:5, Funny)
Parent
Yes, but you forgot the most important detail (Score:5, Funny)
If you are going to troll, at least be on-topic.
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Re:Will my tin foil hats (Score:5, Funny)
> not sufficiently psychoactive.
Wrong: only tin is effective. Why do you think aluminum foil was invented? It only exists to mislead fools like you into believing you are protected.
Parent
Paging Dr Moggles (Score:5, Funny)
My cat gets through tins of Whiskas extremely rapidly. Perhaps scientists can interview him.
lead free solder (Score:5, Informative)
Re:lead free solder (Score:5, Informative)
This makes it a bitch to visually detect bad solder joints also. Not only are they dimpled/mottled, the solder does not wick up onto leads like tin/lead. The leads just sort of mush down into the solder paste. Maybe this is less of a problem with the newer leadless packages, but for older SOIC packages it makes visual detection of defects more difficult.
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Re:lead free solder (Score:5, Insightful)
LOL! You've never heard of Analog?
Visual inspection is key to debugging crucial and intermittent errors due to things like badly soldered bypass caps and ground bounce. Put that in your JTAG and smoke it.
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Re:lead free solder (Score:5, Informative)
I've been seeing heat related issues, some component manufacturers have removed the lead but their parts do not hold up to the heat required for no-lead reflow and wave soldering. We're having parts not only fall out during testing but getting field failures back. This is for non-electrolytic capacitors a ceramic surface mount type and a through hole mylar type.
I've been seeing some units that were done with no-lead less than a year ago where parts are falling off the board. These were some of our early no-lead units so they'll just warranty them and replace the boards.
As to the tin whisker problem NASA has a lot of information on it.
http://nepp.nasa.gov/WHISKER/ [nasa.gov]
But I can't see where they're following their own advice if it means it's a 'show stopper'
http://www.nasaspaceflight.com/content/?cid=4537 [nasaspaceflight.com]
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Exception (Score:5, Informative)
One thing to remember is that safety control and monitoring products like fire alarms, but probably also car electronics, are excepted from the RoHS directive until at least 2012, possibly until 2018, but there's really no fixed date set yet. So yes, your DVD player might die, your car probably won't.
Does it matter? (Score:4, Insightful)
Re:Does it matter? (Score:5, Funny)
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Re:Does it matter? (Score:5, Interesting)
Yup...back to a day when people AND companies took pride in their engineering and craftsmanship.
I know now why some of those old McIntosh tube amps from the 60's still sell for $1200 and up. Things built back then were built like tanks.....and meant to last.
Sad you no longer see that in today's disposable society. Strange that in this day or people trying so hard to be "green", that these same people don't demand that companies built products with such quality that they will last and not have to be replaced every other year.
Parent
Re:Does it matter? (Score:5, Insightful)
There really aren't that many consumer electronics items from the 1950s and 1960s in general use, even when they're compatible with "current" standards. The exception are a few items, like those you mention, that were expensive then and are expensive now. There were hundreds - possible thousands - of millions of radios and TVs made during that time, for example. These are 100% electronic items, unlikely to have failed due to mechanical problems (wear and tear), nor incompatible (in practice) with current standards and systems. Where are they now?
There are items made today that will still be in use in 40 years time, but the number is small, and as with the previous example, they'll be the obscure, highly priced, built-by-craftsmen objects. The "decline in quality" meme is a myth. If it's built in a factory, for the mass market, it isn't - and never has been - in the manufacturer's best interests to make it last for more than a decade. Exceptions exist - but they'll always exist. And, to be honest, there's a remarkable amount of stuff hitting landfills these days not because it fails to function as designed, but because it's obsolete. I suspect the number of 8088-based PCs that could still be working if their owners hadn't put them in the trash would probably number in the tens of millions. And that was hardly an industry where quality was considered a priority.
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Well,, I can only say... (Score:4, Funny)
I blame Mic..hang on..
The RIA...Uh..
In Soviet Ru...Damn..
SCO probably...fu..
Does solder run Lin...um...
Bah!
Re:Well,, I can only say... (Score:5, Funny)
You have wasted your time reading this signature
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NASA Are Worried (Score:5, Informative)
http://nepp.nasa.gov/WHISKER/ [nasa.gov]
Ganty
Tin Whiskers are fact (Score:5, Informative)
Re:Tin Whiskers are fact (Score:4, Interesting)
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Re:Tin Whiskers are fact (Score:5, Insightful)
As referenced in another comment, NASA Goddard Space Flight Center does indeed seem pretty concerned:
http://nepp.nasa.gov/WHISKER/ [nasa.gov]
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Re:Tin Whiskers are fact (Score:5, Informative)
Since 1994 the Aerospace and Military industry have been using commercial components to keep down costs as a result of the Perry Directive. This means that while the assemblies are manufactured using Tin Lead (Sn/Pb) solders, the components are now supplied with a Lead Free solder finish on the solderable terminations in order to comply with the RoHS requirements on commercial equipment. The problem is that different manufacturers have different finishes, and the suitability of that finish can very much depend on the design of the component (surface mount or through hole technology) and the design of the PCB to which it is attached (ground plane design), as well as the type of lead free solder that has been used.
In addition, some lead free solders (such as Tin Bismuth) which have lower melting points that traditional Tin/Lead, leading to poor solder joints if mixed with a tin/lead process.
To summarise, the problems that can be caused by using lead free solders are significant and there are more problems than just tin whiskering. The solution is knowledge of the problem and careful assessment of every component and processes used if the product is going to be used in a long life, high reliability product, irrespective of whether the product comes under the RoHS are not.
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Built-in obsolescence (Score:5, Insightful)
Look at it from the manufacturer's point of view. There's a chance that any piece of consumer electronics is now going to wear out and die even faster, causing people to buy replacements more frequently. Sounds like a great deal for the manufacturer with no downside. They don't have to pay to dispose of these things properly. And no, chucking your old electronics in the trash is not the proper way of disposing of them, unless you like cadmium, mercury, hexavalent chromium, and brominated flame retardants seeping into your drinking water.
Make manufacturers bear the ENTIRE cost of properly and safely disposing of their products, and overnight we'd have cleaner, greener, more long-lasting and durable products.
Re:Built-in obsolescence (Score:4, Insightful)
Very idealistic of you but manufacturers will NEVER bear the cost, it will be passed on to the consumer who will then bitch and moan to their government representation that they are being gouged. The manufacturers will then play the victim, "It's the big bad government restricting our ability to provide you with cheap goods". Now Mr. John Q. Politician is stuck in a real crap hole because the next election is coming up soon and his constituents are angry at him because they are paying what they perceive is too much for certain goods. Also the manufacturers lobby who funded his last campaign are threatening to fund his competition who has promised to rescind any laws that keep the manufacturers from doing business as usual. To compound John Q. Politician's problems the manufacturers are saying they will have to move their factories to more friendly territory in Asia so they can continue to stay competitive providing cheap goods. This would cause thousands of jobs to be lost among Mr John Q. Politicians constituency and many thousands more job losses among the constituency of his colleagues who will refuse to endorse him if he goes against a bill that will hurt their own chances of re-election.
Now he is facing pressure from his constituency, lobbyists, and even his own colleagues.
What do you suppose Mr. Politician does? Stick to his guns and fight the good fight? Hell no he doesn't. He votes to rescind any law that forces the manufacturers to bear any costs that will be pushed onto consumers. Why? because if he doesn't he will be voted out of office and the guy who takes his office will do what he refused to.
Is it right? No. Do I agree with it? No. But thats the way it is.
Parent
Re:Built-in obsolescence (Score:5, Insightful)
Very idealistic of you but manufacturers will NEVER bear the cost, it will be passed on to the consumer who will then bitch and moan to their government representation that they are being gouged.
It worked for catalytic converters, (and as a result unleaded gas). It's worked for low-sulphur diesel. It's worked for air bags. All of those examples likely cause higher prices for consumers that are passed on from manufacturers. I recall auto makers making these exact same arguments against airbags, and nowadays people are afraid of any used car without them. I don't recall any politicians being thrown out of office for making these requirements.
I'm sure there were some naysayers, there always are. The trick is you just have to sell it to the public. Not everyone is a dumbass that only cares about saving a few pennies on electronics.
Right now it's a pain in the ass to get rid of electronics. A lot of garbage collectors won't take them. Cities sometimes do, but you have to bring them to a special collection place, often many miles away and open odd hours. Put something in the legislation that anyone that sells electronics has to also take them for recycling. In Minnesota (and likely other states) we already do this for motor oil.
Parent
According to the web (Score:5, Informative)
http://nepp.nasa.gov/WHISKER/background/index.htm [nasa.gov]
http://www.calce.umd.edu/lead-free/tin-whiskers/ [umd.edu]
From what I can tell from these links there issue is still present in lead-free solder, and very much an issue in certain conditions. I have not seen any pages which indicate long-term solutions, though it would be interesting if someone can turn one up.
Another link:
http://www.national.com/analog/packaging/leadfree [national.com]
Fact (Score:5, Interesting)
The symptoms were always the same. The radio would be working fine one minute and be stone-deaf the next. Sometimes just opening the cabinet door would be enough to dislodge the whiskers and remove the short. But it always returned a few days or weeks later. We got to the point where whenever we were sent out to fix a deaf base, our first repair technique was to take a large screwdriver and rap the cavities with the handle a couple of times, hard. We got some funny looks from the customers but they were happy to be back on the air.
GE finally admitted that the plating was the problem and shipped us a bunch of cavities with a different alloy to use as replacements. They never would tell us what the difference was. Curious, we disassembled some of the old cavities and shook out tiny metal slivers that were finer than a human hair. Some were up to a centimeter in length.
All of the radios we had problems with were less than five years old at the time.
On a somewhat unrelated note, a friend of mine works for a company building avionics. They're still using Lead/Tin/Silver solder for US military contracts. He thinks they know something the rest of us don't.
Re:Fact (Score:5, Funny)
Parent
Not been taking notice? (Score:4, Funny)
Is lead truly that dangerous ? (Score:5, Interesting)
Re:Is lead truly that dangerous ? (Score:5, Informative)
Parent
Re:Is lead truly that dangerous ? (Score:5, Informative)
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Re:Is lead truly that dangerous ? (Score:5, Informative)
The risk is likely more to people repairing and building electronics than to the consumer. The last transmitter tech that I worked with was adamant about handwashing and always had a high wattage light positioned over solder work so that rising hot air would draw lead fumes up and away from his face.
People who hand load ammunition face a similar long term but real risk of lead exposure.
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Re:Is lead truly that dangerous ? (Score:5, Funny)
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Re:Is lead truly that dangerous ? (Score:5, Funny)
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lookit!!! (Score:4, Interesting)
CRAPacitors failed way before tin whiskers (Score:4, Informative)
Reprinted from my blog (Score:5, Interesting)
More recently we got something called "the restriction of the use of certain hazardous substances in electrical and electronic equipment" or RoHS. RoHS prohibits the sale of materials containing more than 1% lead in the EU. (Old-style electronic assemblies use 37% lead solder.) RoHS came into force in 2006 but research into lead-free electronics began decades ago. Initially researchers tried pure tin plating, which lead to tin whiskers. Some products marketed in the late 90's even failed from this problem. But researchers did not throw up their hands in despair. RoHS has led to innovations in metallurgy to the extent that a circuit board designer can now choose from half a dozen different alloys. Today only 2% of printed circuit boards use tin plating.
Some of these new alloys use gold or silver finishes over copper. These are completely immune to tin whiskers. The most popular new system eliminated the plating step, attaching components directly to the bare copper using chemicals called Organic Solderability Preservatives. OSP leads to stronger and more durable assemblies than even the old tin/lead process.
The whining we see today on the subject of RoHS mirrors almost perfectly the doomsaying seen when California began regulating automobile emissions. There was at that time a tremendous amount of yelling about how the catalytic converter spelled the end of civilization as we know it, and only a moron would take the lead out of gasoline. But soon afterwards we saw the introduction of clean, efficient, powerful cars by Honda. Honda was even able to meet California emissions standards without using catalytic converters or even fuel injection. Their brand of engineering eventually trickled down to even the most benighted American car maker, and California emissions standards are now in force in every industrialized nation.
I would expect to see the same thing with RoHS. We have only just entered the initial stage of complaining. The tin/lead dinosaurs with backwards-looking engineering departments face an existential crisis. In other design houses the challenge of lead-free assembly is being embraced as a competitive advantage. Those who can adapt to RoHS will thrive and those who cannot will clearly suffer.
Cringley brags about a 1966 Thunderbird with a 428 cu. in. motor, a car so heavy, so polluting, and so slow by modern standards that it would be impounded by CARB and laughed off a drag strip by a base model minivan. As time goes on I think Cringley's views on the metallurgy of printed circuit boards will seem as antique at that T-Bird.
RoHS caused one of our boards to catch FIRE (Score:5, Informative)
Well here are a few facts... (Score:4, Informative)
Any whiskering is far more likely to be a result of board contaminants than just the tin migrating. Modern solders are less forgiving of bad handling practices.Poor flux choice and board cleaning practices are normally to blame for many faults. Changes in board cleaning practices to eliminate various chemicals means that the industry has had to learn how to do things again.
So, while modern practices might be less forgiving, any faults are really just a result of poor processes.
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Re:Well here are a few facts... (Score:5, Informative)
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Re:Well here are a few facts... (Score:5, Informative)
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Re:Well here are a few facts... (Score:4, Funny)
Parent
An attempt to discredit WP with lies, I say. (Score:4, Informative)
More importantly, where in "the Wikipedia page linked to above" did it state "that tin whisker problems 'are negligible in modern alloys'"?
I saw nothing that said that in current version, and it hasn't been edited (minor or otherwise) since June 13th [wikipedia.org]. I certainly cannot find that single-quoted statement.
I am all for scrutinizing Wiki pages, and not using unverifiable statements [wikipedia.org] from them, but I will not support discrediting them on material that was not written on them in the first place.
Parent
Re:An attempt to discredit WP with lies, I say. (Score:5, Informative)
""Tin Whiskers" were a problem with early electronic solders which were coincidentally lead-free, and lead was initially added in part to eliminate them. These problems are negligible in modern alloys,[citation needed]"
the only metal I've heard of as being whisker free is lead, though, even gold silver and copper can whisker.
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Re:obvious answer (Score:5, Insightful)
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I wouldn't go that far (Score:5, Interesting)
Also, when a philosophical-minority or fringe group tries to take over a highly-watched article, administrators eventually silence them if they insist on using unreliable sources or not keeping the article in "proper balance," where "proper balance" reflects the real-world opinions on the subject. Pseudoscience, alternative-history, and similar-subject proponents tend to get banned if they aren't careful.
Low-traffic articles nobody cares about are very vulnerable to this kind of abuse though.
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Re:I wouldn't go that far (Score:5, Insightful)
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Re:I wouldn't go that far (Score:5, Insightful)
And that's different than a commercial information source how?
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Re:I wouldn't go that far (Score:5, Insightful)
I don't get all the hate for Wikipedia. So it's not perfect, well neither is the Encyclopedia Britannica, but for me Wikipedia is the single most useful resource on the internet second only to Google, and even that may be a tossup because Google often just links me to a Wikipedia page. I'm there dozens of times every day, whether it be looking up something I saw on TV, an actor's name, a musician's discography, or something I just read about [wikipedia.org].
It's a shame such a valuable resource takes so much heat. Maybe it has its problems but it's alot more accurate and alot less opinionated than the average webpage you'll find on any given topic, and honestly it doesn't really matter to me that the article on Chevy Chase [wikipedia.org] hasn't been published in a scientific journal for peer review.
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Re:Cars (Score:5, Insightful)
Especially when they ARE drunk/distracted/incompetent.
Automobile systems are very well designed to fail gracefully or just not matter much when they crap out. (That's also why drive-by-wire is a stupid idea.)
The average car is driven by a mechanical illiterate who barely maintains it (washing does not count) and is designed accordingly. I am an experienced mechanic and know whereof I speak.
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