[HN Gopher] Tin whiskers: What happens when they spontaneously e... ___________________________________________________________________ Tin whiskers: What happens when they spontaneously erupt? (2018) Author : forgotthepasswd Score : 139 points Date : 2022-03-10 16:21 UTC (6 hours ago) (HTM) web link (www.microcontrollertips.com) (TXT) w3m dump (www.microcontrollertips.com) | atesti wrote: | Does anybody from Germany know where I can still buy leaded | solder? Unfortunately I forgot to order a lifetime supply while | it was still available | tejohnso wrote: | This is very surprising to me. I had no idea that certain | conductors had some kind of (stochastic, according to robomartin) | built-in time delayed short circuit mechanism that will, without | question, manifest itself given enough time. | | Like some kind of natural electronics prank. | voakbasda wrote: | If you were feeling particularly cynical, you might wonder | whether this phenomenon has been incorporated into shipping | products, such manufacturers would be assured that their goods | would fail shortly after the warranty expired. | dmitrygr wrote: | Use lead solder, like NASA does: easier to use, and no whisker | issues. Just wash your hands afterwards | mmastrac wrote: | Better to solve these issues long-term. Lead's external costs | in full product lifecycles are just too high. | dmitrygr wrote: | As you read in TFA, there is no known solution, nor even a | known cause for whiskers | mmastrac wrote: | No known cause or solution _yet_ | adrian_b wrote: | It is extremely unlikely to ever find any solution to the | tin whiskers problem, other than alloying tin with toxic | elements, i.e. either lead or antimony. | | The reliability problem could be solved only by replacing | soldering with another method of making electrical | connections during PCB assembly, e.g. thermal/ultrasonic | welding of copper on copper, metal deposition in vacuum | etc. | | While replacing soldering is possible, any known | alternative method would hugely increase the price for | the assembly of electronic equipment. | | Soldering is not used because it is a good method for | making electrical connections, but because it is | extremely cheap, allowing many thousands of connections | to be made simultaneously, during a pass of a PCB through | a reflow oven, or over a soldering wave. | hulitu wrote: | > The reliability problem could be solved only by | replacing soldering with another method of making | electrical connections during PCB assembly, e.g. | thermal/ultrasonic welding of copper on copper, metal | deposition in vacuum etc. | | The whiskers are not related to soldering. Of course | there are some soldering issues which facilitate whiskers | but that's about it. Tin is a normal plating material so | you can find whiskets in places which were not soldered. | Animats wrote: | _The reliability problem could be solved only by | replacing soldering with another method of making | electrical connections during PCB assembly, e.g. thermal | /ultrasonic welding of copper on copper, metal deposition | in vacuum etc._ | | There's been some interest in laser welding for PCB | assembly. But most modern components are not designed | with the pins out where you can get at them with a laser | beam. Laser welding is commonly used to weld the | connections in automotive battery packs, so it does work. | Animats wrote: | If you can get the parts you need in SSOP or TSSOP | packaging, with the pins visible from straight down, | laser brazing might work. | | Brazing is done at higher temperatures than soldering, | but with a laser, you can apply the heat to just the area | of interest, and hopefully not cook the ICs. Laser | soldering already exists, and there are laser cutters, so | adapting one for laser brazing ought to be possible. | | The advantage of brazing is that you can use many more | materials, most of which don't contain either tin or | lead. Low-cost aluminum brazing rod or wire might work. | Working temp around 700C. This is going to take careful | heat management. Worth a try for aerospace applications. | formerly_proven wrote: | Okay, so here's what's what. Tin whiskers have been known | for ~100 years. Originally solder was just tin. Lead was | added specifically in the 30s or so to avoid tin whiskers | [1] though nobody knows why that works. RoHS/lead-free | has been around for ~20 years and there hasn't been a | definitive solution. | | [1] (and because Pb63Sn37 or the inexplicably more | popular Pb60Sn40 are eutectic and near-eutectic, | respectively, which is nice for wire dipping and related | sports) | iancmceachern wrote: | Yeah, and we're not allowed to even put it in products | anymore by law (RoHs, reach, etc) | Steltek wrote: | On the contrary, I am not NASA. I'm not even a consumer | electronics company. I'm a hobbyist at home, soldering things | at my desk or table. Lead-free is the least of my problems when | building something and I don't believe "just wash your hands" | is sufficient for cleaning my workspace (or kitchen table?) of | possible lead contamination. | alar44 wrote: | It definitely is enough. I don't know where the myth that | looking at lead kills you started, but unless you are eating | it or breathing it in (soldering is not hot enough to | vaporize lead) there's nothing to worry about. | JaggedNZ wrote: | Fellow hobbyist here. Actually your biggest health risk is | industrial asthma from flux fumes. I know professionals who | have spent a good fraction of there lives soldering with no | lead poisoning issues. Lead needs to be consumed or inhaled | for it to be an issue. The guy I meet who did have lead | poisoning, large bore rifle shooting coach, from spending to | much time at the "wrong end" of the rifle range. Lots of lead | dust there. | Flozzin wrote: | I wouldn't recommend this. If you do use lead soldering, make | sure you don't breathe in any fumes. | foldr wrote: | The trick is not to end up inhaling or eating the solder in | its solid state. This is actually quite difficult to avoid, | as cleaning the tip of your iron will create lots of tiny | solder balls that fly everywhere and can persist in your | environment. | | Personally I would say that in hobbyist electronics tin | whiskers are the least of your concerns when it comes to the | reliability of the devices you're making. I wouldn't risk | using leaded solder even if the risk is low. | mrob wrote: | Agreed. This, not lead fumes, is the real danger of leaded | solder. You can't hand solder reliably without cleaning the | iron, but both of the common cleaning techniques (damp | sponge and brass wool) inevitably break the soldier into | tiny balls, which bounce and roll all over the place. They | can get caught in clothes, and from there they might end up | getting into food. With the safe dose for lead being zero, | I don't think it's worth the risk. | trhway wrote: | During my elementary school years (beginning of 198x | USSR) the lead was a go to material for a lot of things - | using campfires we melted the lead out of Navy cables and | batteries (from the Navy dumps), no gloves, no masks, and | made a lot of things out of it - toy action | figures/soldiers for example, weights and weighted hooks | for fishing, bullets for DYI guns, gear for some games, | etc. (I'm a drop-out from PhD. program at a top Russian | Math school - didn't see money in it and thus went into | programming, so i guess the few IQ points i lost due to | lead (i score usually about 130) is what caused such poor | judgement :) | foldr wrote: | None of those activities pose the same risks as soldering | using leaded solder, for the reasons given above. (You | are unlikely to end up ingesting significant quantities | of the lead.) | | It's probably worth emphasizing that this is risk with | home soldering, where you're likely to eat and solder in | relatively close proximity, and without being completely | rigorous about changing your clothes and cleaning. | the-dude wrote: | The boiling point of lead is 1749 degC (3180 degF). | turminal wrote: | That by itself does not imply fumes cannot form at lower | temperatures. | the-dude wrote: | Great. If we follow this line, standing next to a roll of | solder is just as dangerous. No need to fire up the iron. | | If lead was so easily dissolved into air, wouldn't we | have had massive issues in electronics factories? I don't | recall ever reading such a thing ( as opposed to | _painters madness_ for example ). Not a native speaker, | probably doesn 't translate too well. | mcguire wrote: | " _Results showed that the mean PbB concentration of the | exposed workers (6.12 +4.61 ug /dl) was significantly | higher than that of the unexposed workers (4.63+3.91 | ug/dl ) (z = 4.96; p = 0.001). There was a significant | association between the blood lead concentrations with | the exposure to lead (2 = 437.72; p = 0.001)._" (https:// | www.researchgate.net/publication/271077842_Occupatio...) | | " _Epidemiological and experimental studies indicate that | chronic exposure resulting in blood lead levels (BLL) as | low as 10 ug /dL in adults are associated with impaired | kidney function, high blood pressure, nervous system and | neurobehavioral effects, cognitive dysfunction later in | life, and subtle cognitive effects attributed to prenatal | exposure. Pregnant women need to be especially concerned | with reducing BLL since this can have serious impact on | the developing fetus._" | (https://www.osha.gov/lead/health-effects) | amatecha wrote: | is that because they inhaled it in fumes, or because they | touched it? or something else? | the_jeremy wrote: | Mad Hatter[0] is a good example in English. | | [0]: https://en.wikipedia.org/wiki/Erethism | kadoban wrote: | Or you could just look at the actual material property | that matters, which I believe is called vapor pressure. | xmodem wrote: | The boiling point of water is 100 degC, and yet my shower | seems to produce an awful lot of steam despite not being | anywhere close to that. | [deleted] | at_a_remove wrote: | You have confused steam with small water droplets, akin | to what emerges from an ultrasonic mister. If it were | steam, you would be shrieking and then dead. | kimixa wrote: | I thought everyone did the experiment of leaving a saucer | of water out and seeing it evaporates over time, despite | being significantly lower than 100c. | | And "Steam" is wooly term for high enough density of | water vapor that you see condensation - often caused by | higher temperatures in the majority of cases people | experience it in day to day life. So it doesn't really | have a precise definition. At what temperature point does | "mist" become "steam?" What %age of the volume of air | needs to be water vapor? If you lowered the pressure | water "boils" at a lower temperature - is that still | steam? | deathanatos wrote: | But it's still water, and it's still moving up and about | of its own accord in the local air which is the point. | That it isn't _technically_ steam doesn 't disprove the | point the person you're responding to is trying to | make... | | The commenter's point isn't that the lead has technically | been boiled, it's that, if we analogize to "steam" in a | shower, I don't have to reach water's boiling point | before I'm breathing in water. Does that translate to | lead: i.e., even if I'm below lead's boiling point, could | I be nonetheless breathing in lead vapor, or something | like that? (I don't know the answer here, which would | push me towards lead-free solder. I.e., I don't know if | the precautions I'd take with lead would actually | suffice.) | jpindar wrote: | No, soldering doesn't send streams of liquid solder | through the air. And if an occasional drip of solder does | splash, it is so heavy, and has so much surface tension, | that it doesn't go far and doesn't stay in the air like | water droplets do. | B1FF_PSUVM wrote: | Good point. Also, steam is invisible. What we see - e.g. | from a boiling kettle - is condensation. | myself248 wrote: | Or just get your blood lead level measured. | | A few months ago, I happened to be at the doctor getting some | other stuff checked out, and the week prior to the | appointment I had done a ton of soldering, like two 12-hour | days bashing out a whole batch of boards, both paste reflow | and hand-PTH work, with a fair bit of sucker rework, and of | course after that the lab needed a good tidying so I emptied | all the suckers and tip cleaners as part of that. All tin- | lead solder. | | Zero gloves, and I only wore a mask part of the first day | (when there were other people around). And actually the | several weeks leading up to that also saw a lot of SMT rework | and other up-to-by-elbows-in-solder sort of activity. | | So I figured, that's kind of a worst-case for my lead | exposure, hey Doc, can I get my blood lead level checked? | Sure why not, it's one extra vial on top of the bloodwork | already being ordered! | | And the results came back below the test's detectable level. | | So as far as I'm concerned, if that didn't do it, I don't | think I have anything to worry about. Now, I'm sort of a | germophobe and I never eat with my hands, so this doesn't | necessarily generalize, but as far as skin absorption or | vapor inhalation, I've gone from "not very worried" to | "abjectly unconcerned" after getting that result. | | I would encourage everyone to get their level measured and | have actual data to make decisions with. Superstition does | not become us. | semi-extrinsic wrote: | The vapor pressure of lead at 300 degC is around 10^-6 Pa. In | laymans' terms, there is zero evaporation of lead happening | during soldering. Ice at -40degC evaporates (sublimates) 10 | million times faster. | | The fumes from soldering are from the flux or rosin, and that | is just as dangerous if you are using lead free solder. | Always use adequate ventilation and/or filtration to avoid | inhaling fumes. | adrian_b wrote: | Besides lead, there is a second element which greatly reduces | the risk of tin whiskers, when alloyed to tin: antimony. | | However the proposals of replacing the tin-lead alloys withe | tin-antimony alloys have been rejected due to the fear that | antimony is also toxic. | | While antimony in high doses is indeed quite toxic, it is less | dangerous as a pollutant than lead, because it does not have | the same tendency for very long time accumulation in animal | bodies and such a strong effect on the nervous system. | 1970-01-01 wrote: | Much more info here: | | https://nepp.nasa.gov/whisker/ | jwilk wrote: | > _as fast as 15 nanometer per second to 1 mm per year_ | | That doesn't sound right. 15 nm/s is ~47 cm/year. | coryrc wrote: | They break off if they get too long and will run out of | material at some point. | greggsy wrote: | I don't think it's a steady growth rate. | RicoElectrico wrote: | > No one has been able to eliminate whiskering, as the phenomenon | is not yet fully understood. | | It's the kind of stuff we should be embarrassed not to | understand. I get that understanding living things can be tricky | due to complexity and issues with controlling conditions, but a | lump of metal? Whatever we find out will at least save us money | in damaged devices, and hopefully drive some progress in | metallurgy as well. | | We had an era in semiconductor manufacturing when despite the | relative simplicity the process was not understood/controlled | fully, which took the toll on yield. E.g. CMOS was super fussy | due to difficulties in creating gate oxide - impurities in air | like halogens made the yield seasonal [1]. But now I assume that | if any problems arise, they're due to bona-fide complexity. | | [1] https://news.ycombinator.com/item?id=28178612 | [deleted] | [deleted] | [deleted] | robomartin wrote: | > It's the kind of stuff we should be embarrassed not to | understand. | | We understand it. Onset is stochastic. Mitigation is impossible | given current regulations in consumer-land. Read my longer | comment for further details. | | EDIT: What I mean by "we understand it" is that we know that | lead-free solder chemistry leads to tin whisker growth. When I | was taking a deep dive into this many years back, the | researchers I was working with at NASA told me "Growth onset | can be 0 days to 3 years after manufacturing. Your guess is as | good as mine.". And, BTW, you can have growth start in a few | days in one corner of the PCB and a few months later elsewhere. | It's a complex relationship of materials properties. | | We know that tin whisker growth in lead-free solder is as much | of a reality as gravity is between two celestial bodies. In | other words, it will happen. We simply have no way to predict | when or how quickly they will grow. It might just be too | complex to compute/predict given the variables involved. | gowld wrote: | That sounds like not understanding it. | robomartin wrote: | Not quite. We understand that we can't build an anti- | gravity device and don't even know how to go about thinking | of one. Understanding that something is impossible (or | likely impossible) is understanding. We might not like the | answers (I sure didn't at the time) yet they are a based on | knowledge and decades of research by some of the smartest | scientists I have ever met. | hulitu wrote: | There are parts of the process which we do not underestand. | Testing is expensive especially at this level and nobody | wants to pay for things which _could_ happen. | semi-extrinsic wrote: | A lot of the challenge here AFAIK is that the process needs to | be understood at the molecular level, where we measure time in | picoseconds (10^-12), while this process takes something like | 10^6 seconds. The disparity is an absolutely astronomical | factor of 10^18. | ChuckMcM wrote: | It really is an amazing phenomena. Effectively atoms of tin are | moving from the tin out to the end of the whisker. We spent a | week talking about whiskering(sp?) in my materials science class | at USC because it was such a big deal in the EE world. | | Prior to that class my world view was that only electrons could | travel through metal, only to find that metal can travel through | metal too! | | Locally at NASA Ames they had an experiment where they had a | bunch of different assemblies being exposed to various conditions | (high electric fields, non-ionizing radiation, etc) and one of | the things they were measuring was the production of whiskers and | other changes in material properties (strength, toughness, Etc.). | Always amazing what we know and what we don't know about what we | know. | zdragnar wrote: | > that metal can travel through metal too! | | I recommend watching clips of mercury amalgamations forming | (nile red has some great videos on youtube). | | There is something about it that is both disturbing and | beautiful to me. | cjameskeller wrote: | That was a welcome rabbit hole. Thank you! | rootusrootus wrote: | > Effectively atoms of tin are moving from the tin out to the | end of the whisker. | | Don't tin whiskers get built from the base up, though? So the | tip was the first thing built, and just gets pushed farther | away. | prutschman wrote: | Could potting prevent this, or can the whiskers "push through" | epoxy? | dr_orpheus wrote: | Yes? In my experience (some spacecraft electronics stuff) this | is also on the list of things where we think conformal | coating/potting helps prevent tin whiskers. But there are still | instances where Tin whiskers have grown and pushed through | conformal coating on a PCB. | | Edit: Go look at the more detailed response from robomartin | robomartin wrote: | No. Can't prevent it. Yes, they can push through epoxy or | buckle under it (which isn't a solution). Read my longer answer | for details. These things are a nightmare. | jccooper wrote: | Yes; satellite boards tend to have conformal coatings, it helps | but it's not a complete solution. (The coatings also help avoid | shorts from junk floating around, and launch vibration.) | Because of the inherent unreliability and difficulty in | replacement, they also try really hard to avoid lead-free | solder requirements. | Damogran6 wrote: | State of Colorado Datacenters got them. The response to them were | weird...if any machine were in any of the affected areas, they | were persona non grata...they could never leave those datacenters | as functional server. | | It DID lever some money for an awesome off-site backup | datacenter...which was eventually our only datacenter for | 'reasons'. | | In our case, I think one of the datacenter's raised floors got | carpeted (don't judge, it predated me, I was equally baffled) and | a grounding issue caused a voltage drift causing the tin to | migrate... | walrus01 wrote: | raised floors in general are a nightmare for | grounding/bonding/differences in potential between racks, the | steel floor structure, the building, and electrical conduits. | | there's a reason why almost nobody builds them new from a | clean-sheet-of-paper design anymore for serious datacenter | applications or ISP/telecom purposes, which are racks/cabinet | on concrete slab and everything overhead now. | | it's _much_ easier to ground /bond everything together using | some very fat copper cables run along ladder rack overhead, and | bond all the racks to that. | robomartin wrote: | I have dealt with the tin whisker problem in the context of | aerospace applications (both space-borne and terrestrial flight), | including extensive consulting with subject matter experts from | NASA. | | The bottom line is quite simple: | | Tin whisker growth onset is a stochastic process. We cannot | predict when it will start and we cannot prevent it. | | Once they start growing it is almost impossible to contain them. | They will poke through conformal coatings such as parylene and | arathane. If they don't, they will buckle (coil-up) under the | coating. | | While buckling sounds like a desirable outcome, this could lead | to shorting of adjacent contacts in todays fine pitch integrated | circuits and components. | | Growth rate can be in the order of 10 mm per year. This means | that adjacent leads of something as mundane as a SOIC-16 package | can be shorted by a tin whisker in 28 days or less. | | The take away is: There's nothing we can do about tin whiskers | that is 100% guaranteed to prevent growth or slow it down by a | non-trivial amount. The only path that prevents their growth is | to use lead-based solder. This is why, as an example, we would do | such things as send out BGA's with RoHS compliant solder balls to | be re-balled with leaded solder. | | Time for a bit of a rant: All my work in this area led me to look | at the RoHS initiative as yet another example of something that, | while well intentioned, it will likely have precisely the | opposite effect from what was intended. | | The fact that lead-free solder is susceptible to tin whisker | growth means that 100% of all consumer electronic products are | ticking time bombs when it comes to failures. This means that all | kinds of consumer, commercial and industrial electronic products | will fail over time in ways we might not be able to explain. The | reason for this is that nobody does deep forensics when products | fail. There is no reporting from the likes of Apple, Samsung, LG, | Visio, Sony and myriad other manufacturers on failure rates and | causes. In fact, they might not even have this data as consumer, | commercial and industrial users simply replace the devices as | they fail and move on. | | In other words, it is likely RoHS has caused --or will cause-- | massively more garbage in landfills. As a simple data point, my | 40 year old HP-41 calculator still works perfectly fine. It is | impossible to imagine a RoHS-compliant calculator not ending up | in a landfill way earlier than 40 years. | | There was a bit of a movement to roll back RoHS around the time | it was being enacted. Going up against many nations and | politicians using "save the planet" to get elected proved | impossible for those who rightly brought-up that the transition | to lead-free solder required far more research before we fully | understood the potential consequences. | | It wasn't about not wanting to go lead-free, it was about making | the move when the science and math indicated that it would not | create the massive problem we now likely have on our hands. The | data on electronics waste due to tin whiskers is probably | impossible to find. It might not even exist. Which is a tragedy. | | If you want to learn more about this, here are a couple of good | links: | | https://nepp.nasa.gov/whisker./background/index.htm | | https://nepp.nasa.gov/whisker/reference/tech_papers/kadesch2... | | https://www.google.com/search?q=tin+whisker&hl=en&tbm=isch | | https://web.calce.umd.edu/tin-whiskers/ | xmodem wrote: | Do you happen to know if tin whiskers have anything to do with | passing current? (in other words, will a device that's in | constant use develop them faster than a physically identical | device that's switched off and in storage) | hulitu wrote: | Yes. Voltage has a big effect on whiskers. | londons_explore wrote: | Passing current means thermal cycling... | | And thermal cycling definitely accelerates whisker formation. | twofornone wrote: | Are there any easy ways to clean up a PCB that's developed | whiskers? And once a whisker erupts on a given PCB, does that | generally indicate that others are likely to form on that board | in short order? | oceanplexian wrote: | Well actually, there is a way, but you might kill said PCB. | | Heat everything up in an oven, the solder will reflow, and | you might temporarily fix the board. It's a similar idea to | the Towel/Xbox 360 fix. I can attest to having successfully | saved lots of random electronics this way. | | All of this started with the eco-friendly alternatives to | lead solder, I have a lot of old computer hardware and | motherboards, and the hardware from the early 2000s is the | least reliable, whereas most game consoles, motherboards, | etc. from the 80s and 90s works flawlessly. To this day I | swear by the leaded stuff for personal use, it flows better, | doesn't crack, and is superior in every way. | robomartin wrote: | All else being equal, once growth starts it is likely to | start everywhere on that board. This is a probabilistic | assumption based on the likelihood of all of the solder on | that board being from the same batch and having been applied | with the same process parameters. The same cannot be said of | the device leads, where each manufacturer and batch could | very well be different. | | It's quite a nightmare, particularly when you are trying to | figure out if this stuff can kill people you want to send | into space. The only real mitigation is lead-based solder and | coatings on components. | | Cleaning? That can be both dangerous and highly ineffective. | The whiskers are very strong due to their molecular scale. | Mechanical brushing might fracture longer whiskers. Then you | have the problem of ensuring that they don't go under devices | or in-between contacts. The process would likely have to be | repeated many times and include both manual and automated | optical inspection as well as x-ray imaging (which might not | be able to detect fine whiskers). And then there's the | reality that you probably don't want to inhale these things | at all. | | So, off to the landfill we go. It is likely better to build a | new board than to try to clean one. I can't even begin to | compute the delta in carbon footprint between making a board | with lead-based solder that will last decades and the | "clean/green" RoHS board that is sure to end-up in a landfill | (cleaning/fixing it is bound to have a massively larger | carbon footprint that making a new board). | HPsquared wrote: | Is this why space electronics often use wire-wound | connections? Maybe welding the contacts together instead of | soldering? | | I assume for the really critical components, you'd need to | avoid solder completely. | sydbarrett74 wrote: | Unfortunately, all consumer electronics companies have | this fetish for making products ever smaller and thinner. | It dovetails with their profit motive: make things less | reliable so we all have to buy more frequently. | Ottolay wrote: | RoHS does not just restrict lead. It also restricts use of | mercury, cadmium, and several toxic compounds. | Steltek wrote: | > In other words, it is likely RoHS has caused --or will | cause-- massively more garbage in landfills. As a simple data | point, my 40 year old HP-41 calculator still works perfectly | fine. It is impossible to imagine a RoHS-compliant calculator | not ending up in a landfill way earlier than 40 years. | | Environmentalists can only wish that people were disposing of | their electronics because of tin whiskers. Long lived consumer | electronics needs a cultural overhaul more than it needs leaded | solder. | ghostly_s wrote: | I did not know these whiskers had been implicated in the Toyota | unintended acceleration scandal: | https://nepp.nasa.gov/whisker/reference/tech_papers/2011-NAS... | dilyevsky wrote: | Miniaturization trend definitely doesn't help here either... | stefan_ wrote: | The _Restriction of Hazardous Substances Directive_ (RoHS) is | not about preventing garbage in landfills, and frankly it 's | been 18 years and the sky is not falling. | MisterTea wrote: | Yes but the parent is not stating that. They are stating that | a "save the environment" effort is not very environmentally | friendly if it makes more waste. | _Microft wrote: | They are assuming that these devices would be used long | enough for tin whiskers to become a problem. I seriously | doubt that RoHS will be causing more waste - because at the | point that devices become unusuable, they are on in the | trash anyways for completely unrelated reasons (think: | bezel to large to be popular, plastic backshell instead of | metal or glass, device is too thick, device is too heavy, | ...). | hulitu wrote: | Tin whiskers continue to grow even after you device is in | the landfill. You basically have a dust of tin which goes | into landfil. | mmastrac wrote: | Saving the environment by reducing actively, acutely | hazardous materials and saving the environment via reducing | landfill/carbon emissions are completely different goals. | | As others have pointed out in this thread, reducing | landfill waste from electronics is a much more complex | problem and just adding leaded solder will not solve it. | nomel wrote: | That assumes waste reduction is the goal, rather than lead | reduction. With toxic, intelligence reducing [1], materials | like lead, maybe some extra waste is a perfectly good trade | off. | | 1. https://news.ycombinator.com/item?id=30600539 | hulitu wrote: | Last i checked tin was not an edible material. There is a | small difference between having tin dust, which you | cannot contain, and having electronics containing lead | which you can colect and store in a warehouse ( asuming | you want to address the problem in the first place). | cinntaile wrote: | Are you saying that electronics devices continuously let | out tin dust so we end up breathing in this stuff? | stefan_ wrote: | Uhm, that is exactly the point that I'm making? That the | goal was never save the environment, but rather reduce the | exposure to toxic-at-any-concentration things like _lead_? | | Hence why I quoted the program name. | Steltek wrote: | Devices are disposed of (becomes waste) long before they | become broken from whiskers. That makes RoHS a net-win by | reducing toxic materials from landfills full of phones with | broken screens and kitschy doodads with broken plastic. | adrian_b wrote: | The sky is not falling in large part because the transition | to lead-free solder was simultaneous with the transition to | electronic devices that are not repaired and which frequently | have a lifetime not much longer than their warranty time. | | Most current electronic devices are dumped much earlier than | when they would fail due to the tin whiskers. | | Many consumer electronic devices made 50 years ago are still | usable without any problems caused by the aging of the | soldering or of the semiconductor devices (but old | electrolytic capacitors may have to be replaced). The | electronic devices that are made now do not have any chances | of such a long lifetime, with the exception of a few devices | made for special requirements, e.g. military/aerospace. | zozbot234 wrote: | Consumer electronics used to break down all the time 50 | years ago. Metal whiskers are not even close to being | relevant when other factors impact reliability and | durability to a far greater extent. | hulitu wrote: | They used to break down and they could and were repaired. | Nowadays if something breaks it goes in the garbage can. | I had an extension cable which died staying in the | basement for a year. When i opened it to check the reason | i was shocked. It looked like a spider net made of dust | but this was metal. | adrian_b wrote: | Consumer electronics used to break down all the time, but | in almost all cases that was due to manufacturing | defects, which were much more frequent, because many | operations that are now automated were still done | manually then. | | The consumer devices which survived infant mortality, | because they were free of manufacturing defects, had a | negligible aging rate after that. | | Modern electronic devices have far fewer initial | manufacturing defects, due to automated production, but | all age much quicker, due to very small component sizes, | lower safety factors, surface semiconductor devices (MOS | transistors) instead of bulk semiconductor devices | (bipolar transistors), lead-free soldering and other | similar changes in technologies. | squarefoot wrote: | > Consumer electronics used to break down all the time 50 | years ago | | But they could be easily repaired. | oceanplexian wrote: | Once things started going to multi-layer PCBs it was the | end of reparability. It's too bad because I have fond | memories of fixing broken components on PC hardware and | game consoles, even as someone who's not an expert and | simply a hobbyist. | alfor wrote: | Does wisker form inside semiconductor also or do they use | metals immune to that? | hulitu wrote: | Yes they do but slower. In the past gold was used for wires | from terminal to pads. Gold as far as i know is not so | subceptible to form whiskers. But gold is expensive and now | they use copper instead of gold. | [deleted] | mmastrac wrote: | After seeing the articles on ice spikes, I wonder if this is | somehow a related phenomenon. | thanatos519 wrote: | Indeed. Maybe they are also related to bone spurs! | jerf wrote: | Remind me more of this, only in slow-mo: | https://www.nature.com/articles/nature.2015.16771 | [deleted] | FpUser wrote: | Accepting RoHS was in my opinion one of the most idiotic | environmental initiatives that was rammed through without much | thinking about long term cost / benefit analysis. | hulitu wrote: | A repaired device is one less device sold new. At the end what | matters is money. ___________________________________________________________________ (page generated 2022-03-10 23:00 UTC)