Every electronic system you own is filled with joints between parts. In the vast majority of those, the joint is soldered. Most people probably know about solder, a metal that liquifies to create a joint, because soldering things is pretty common. Plumbers solder copper pipes (when they still use copper pipes!), jewelers solder jewelry, and so on. You may not realize, though, that European Union initiated a program in 2003 to eliminate lead in the solder used in electronics. In 2006, the RoHS rules, short for Reduction of Hazardous Substances, went into effect banning the use of lead in solder. In the hundred years since electronics went into routine production, quite a bit of research went into creating the ideal solder alloy, and for most of that hundred years, a 63% tin 37% lead eutectic alloy has been preferred for most electronics soldering. (Note: I couldn't tell you why, but RoHS is usually pronounced "row-hoss").
When the use of lead was ordered halted, joints had to be made somehow, so the industry desperately searched for a replacement, often creating components with bright tin coatings - which looked like a freshly soldered surface (commonly called a "tinned" surface, although it's solder). Unfortunately, some of that hundred years of research had taught us that a bright tin surface is the worst thing you want to use, and that knowledge was somehow "lost". Bright tin surfaces tend to grow "tin whiskers" which have caused many failures, and the matte finish tin finishes grow whiskers at a lower rate. In one of the trade magazines, Avionics, author Walter Shawlee II writes:
This is a phenomenon so bizarre it almost sounds like science fiction, but it is all too real, and frequently fatal to circuit operation when it occurs. The chemical mechanism is poorly understood, but tin-plated leads and solder joints (without lead) begin to grow tiny straight hair-like crystals with or without current flowing. These can extend from track to track, pad to pad, between any leads and other metal areas. The tiny whiskers are highly conductive, and can result in catastrophic or intermittent circuit failure. Amazingly, no PCB surface treatment, post coating or solder masking will prevent it. This is a mechanism largely unique to tin (Sn) plating or solders that contain no lead, but can also occur in some other metals from palladium to zinc, but generally requires elevated temperatures or pressures, while tin whiskering occurs in all normal Earth environments, and even in space.(image from NASA Goddard Space Flight Center)
When the ROHS rules were formulated, they specifically exempted high reliability areas like military, space or aviation, but missed something important. The companies that make components don't want to have multiple production lines for their parts, and if they just have one line they'll make the line that sells the most, the lead-free line. Companies in the "high reliability" sectors buy components that are lead-free, but then solder them with full lead solder to improve the reliability. Even so, a few multi-million dollar satellites have been lost, and the failure attributed to whiskers. Many more cheaper, earth-bound systems have failed and the whiskers found. Tin whiskers have even been implicated in the Toyota "runaway acceleration" problem which has claimed a few lives.
But the RoHS lead-free policy is more stupid than anything. By far, the biggest use of lead is in batteries and they were left alone! Shawlee, again:
Just for some clarity, the total world use of lead is about 90 percent for batteries, and the amount used in electronics (excluding batteries) is all of 2 percent. So, of course, target the 2 percent. Further, of the lead in landfills (the supposed concern of this directive), the overwhelming majority is coming from the disposal of TV CRTs and monitors, which can contain up to 2 kg of lead per tube, not from circuit board assemblies, by a massive ratio of 9 to 1.If you owned a bunch of CRTs and knew the ban was coming, what would you do? Working CRTs were trashed to the landfills to get rid of them before penalties came into effect for not recycling them properly!
It’s rational to ask, after a few years of RoHS policy in force, does this effect ever really cause any problems? As it happens, yes, and some examples are so spectacular that it’s amazing they have not reversed the policy for RoHS. In Europe, the most impressive example was $1 billion recall of Swatch watches from Switzerland, as the use of lead-free solder caused a roughly 5 percent watch failure rate in 2006. The “solution” to this problem was yet another rule exemption, and lead was again used in Swatch construction. A real RoHS policy triumph there.As you might gather from the Swatch and Toyota examples, this problem is happening in consumer systems. The EU has mandated a new failure mode into every electronic item sold. Don't think of just your TV or your MP3 player: newer cars have several microprocessors in them. Don't forget your air conditioner, your range, the electronics embedded in everything. When I was a kid, my parents had a black and white TV bought in the mid '50s; they junked it and we got our first color TV when I was 15. My wife and I had an RCA color TV, our first "big screen" at 27", for 21 years. I think it's a safe bet that the number of TVs being sold today which will last 21 years is going to be quite a bit smaller than it was before 2003. The irony is that today's solid state electronics and LCD screens should be more reliable and last longer. That means landfills will be getting more broken electronics than they need to. Another stunning policy victory for the environment right there, too.
Tin whiskers growing on a variable capacitor (source)
I wonder if this is why my DLP TV died. Capacitors went out.
ReplyDeleteAs others have said, the capacitor issue was a problem with the factory that makes most of the cheap aluminum electrolytics. It was in China (IIRC). They cheated on materials and made them barely able to withstand the voltage applied. In general, you don't want to get closer to the cap's rated voltage than 80%, and 50% is safer, still.
DeleteThem whiskers is just bizzare.
ReplyDeleteLead is good - used knowledgably. One would think that lead poisoning would have been rampant among plumbers, tinners, roofers et al with the use of lead melting pots - but does the evidence exist?
Certainly lead is a toxin - no doubt - but the hysteria surrounding its use defies reason. Most of us of a certain age grew up in houses coated in lead, and drank water from pipes soldered with (if not consisting of) lead - without problems.
And the lead sinkers, pellets, toys etc.
Indubitably, local water chemistry could create additional problems with lead contact, but not sufficient enough to engender global "solutions".
"The EU has mandated a new failure mode into every electronic item sold." Yep. Create the problem, sell another probleem creating "solution"
itor
Capacitor failure is caused by an different mechanism.
ReplyDeleteGoogle for "bad caps", and you'll get a very interesting story of industrial espionage.
I actually prefer 60/40 over 63/37. 60/40 wets better, and flows out better. If you don't *need* to use 63/37, don't use it. When I was a NASA certified soldering operator (my cert expired last year. The new company won't pay to renew it), I had quite an interesting discussion with my instructor. He basically agreed with me, the 60/40 is better for general use, as it's easier to solder with.
And I have several 10 pound spools of 60/40, and a couple of 5 pound spools of 63/37. I should be good for quite a few years!
I have a few spools of lead solder around the house and recommend it to anyone fixing or building electronics. Screw the EU. The few hundredths of a percent of lead in the electronics scrap from home-repairs isn't going to matter compared to the rest of the landfill.
DeleteAt an electronics shop where I do the books the repairs are almost always either cracked solder connections or bad capacitors. We call them "CRAPacitors". One of the techs who used to work there called them "Cat-piss-assitors".
ReplyDeleteCaps go bad a lot. Cheap Chinese crap.
Speaking of industrial espionage, they just discovered last month that the Chinese-made CPU chips in a lot of US military and government computers had back doors in them that let the Chinese spy on them.
The "Greenies" in question did not write the legislation restricting lead use in electronics manufacture. Research in the issue concluded that heavy metals, including lead, in electronics and batteries BOTH ought to be recovered rather than disposed of in landfills. Whether the ratios are 9-to-1, or 50-to-1, or whatever, is irrelevant. The core point of the legislation, written BTW by legislators, was to assume some long-overdue environmental responsibility. In short, recycling the materials in both, whatever the commercial ratio, should be the ultimate goal. This ought to be commended by everyone who enjoys untainted wellwater at their post-apocalyptic bunkers, by hunters of ducks you can actually eat after you've gone through the trouble of shooting them, and notably those who just enjoy scenic background wallpaper on their blogsites, preferring to believe it isn't littered by old sinkers and car batteries.
ReplyDeleteYes, the legislation had negative unintended disposal consequences. Yes, Chinese caps are garbage. Yes, tin whiskers affecting critical municipal or defense systems pose some very frightening possibilities. There arise unforseen complications as a result of every well-meaning legislation, but we need to strike a mature balance between the value of our ecosystems, and TVs (your example) that simply last longer. To obliquely dump blame on "greenies" for the tin whisker phenomenon, along with the inherent (and tragic) flaw of specifically-targeted legislation to consistently fail to meet holistic goals, is frankly childish.
I was a bench tech for Pentax, used more than my share of solder and worse things, and know more than a few of your maligned "Greenies." Despite the environmental legacy of 50 years driving Volkswagons, Greenies are pretty effing good at recycling and sustainability. You might stand to learn a couple of things from them.
I never know if I should answer a comment on an old post; it's possible someone was doing a random crawl around the web, dropped a comment and will never be back, but let me add a few thoughts for posterity.
DeleteHow about this: how about before something essential is outlawed that we have a replacement for it? How about before the heavy, clumsy, uncoordinated hand of government gets involved they get some details right first? Sure, lead is toxic, but guess what: another few years accumulation in landfills to get the replacement right so that people don't get killed and expensive projects ruined by a hasty replacement just wouldn't make much difference, would it? People have been killed by this, you know. Or do the lives not matter to you? We could have saved that by taking some of the fat bureaucrat paychecks and paying some material scientists to develop alternatives. No, let's just outlaw solder and whatever happens, well, omelets and eggs, you know?
I'm not saying lead isn't toxic, but frankly isn't it stupid to go after the 2% and leave the 98% alone? It's nice that the greenies behind ROHS wanted to take care of the 98%, but they didn't, did they? And the point about the old TV story wasn't that they last longer, it was that they will go into the landfill sooner and create more pollution, which sort of acts to negate the whole legislation.
I'm saying that Government rarely, if ever, gets details right. Rarely, if ever, gets legislation right. This could have gone a whole lot better for everyone and "the environment" if there had been more thought and intelligence involved. The regulators act like a new chess player that can't think one move ahead. That's really all it took.
I have no complaints about recycling. Car batteries are one of the most recycled consumer items out there, along with aluminum cans and plastic bottles.
ReplyDeleteI agree 100% with Silicongraybeard about at least allowing time to find an acceptable replacement before outlawing it 100%.
Several companies I worked with spent 100's of thousands of dollars, and scrapped a LOT of product before they were able to use the "acceptable" replacement solders.
Hi SGB and drjim, thanks for the reply,
ReplyDeletePresumably electronic waste, regardless of vintage, quality or solder recipe, will now get recycled. So despite all our government bashing, I think we can all agree that this one piece of legislation, in isolation, is very beneficial. It could also be argued that it was long-overdue.
So let's review the lead-free solder legislation; there was what seemed to be a viable alternative to leaded solder which turned out to be alarmingly dangerous crap. In retrospect yes, it'd be nice to assert that we should have taken our time. But frankly, the tin-whisker phenomenon was so astonishing, and took some time to progress, it's doubtful anyone would have predicted it. So here's an example of a piece of legislation which was (remarkably) NOT long-overdue, for a change.
People died; accelerators pinned and human beings died horrible deaths. I do not underestimate the tragedy and pain that occurred. People were also suffering and dying from neurological damage prior to the legislation. What would you have done? Tell industry to try to find a replacement but hey, no pressure?
I don't disagree with you that government rarely gets the details right. But let's make a decision about what we all claim is wrong with government on these issues; either it acts too slow or it acts too hastily. But it acts.
Perhaps the past is in this case prologue; when CFCs were identified as wiping out the ozone layer, we had a runaway situation where the CFC molecules were splitting apart and binding to the ozone molecules at thousandfold ratios. There was a lot of hemming and hawing, even claims of economic disaster if ladies didn't get their hairspray products. (!) The ban on CFCs forced industry's hand at developing (with gradually-evolving success) a viable replacement. Left to their own devices, industry wasn't going to do a thing about it. Nobody was terribly concerned about penguins or phytoplankton.
Reality check: Carter was president. We're still living with that legacy today. The ozone holes (now two) are only now starting to recover. I can point blame, again, to the Chinese for continuing to manufacture & sell the interim formulas which still damage the ozone. And I can point blame, again, to our government for not being aggressive enough with international moratoriums. (moratorii?)
As for the popular sport of disparaging the greenies whenever convenient; they are the only ones around actually giving a damn and trying to do something constructive about it. That the legislative solutions are merely reactive, and/or not comprehensive (or holisitic; my term) enough can be blamed on the maddeningly myopic process of writing legislation in fractious democracies.
In the case of CFCs, it took a government fresh off the lessons of DDT to light a fire under the asses of industry, that the ban is happening whether there's a replacement or not. Regrettably, in America sometimes that's exactly the path it has to take. It won't happen otherwise.
(sorry for commenting on such an old post. My attention was drawn by the 3D anaglyph of the Apollo Lunar Module you had posted, which appeared on a Google search)
There are so many things I could go off on in there... but I won't. This is an old thread, let's just let it decay to the background.
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