Lead free solder - Studies by NASA - Page 1
Forum section: electronics / general

author: vivaT
author_rank: Contributor
timestamp: July 23, 2012, 02:23:41 am
content: I found a very interesting page after knowing next to nothing about the dangersof using lead free tin/copper solder and the ROHS on a NASA page below.If the gallery isn't tickling your curiosity may i suggest a read through a 2011pdf which not only lists many way Tin whiskers can cause unknown faults throughthere tiny size to a summary of the lead "thrown away" in solder vs batteries.Oh and did i mention conformal coating saved the shuttle from tin clips ? No? then read on...Lead-free Electronics Reliability -An Updatehttp://nepp.nasa.gov/whisker/reference/tech_papers/2011-kostic-Pb-free.pdfhttp://nepp.nasa.gov/whisker/

author: digsys
author_rank: Unknown
timestamp: July 23, 2012, 02:44:02 am
content: The majority of repairs I've done on vehicle ECUs (some are dumb enough NOT to get an excemption) andother European equipment (because these have been around a while now) have ALL been from eitherthe solder separating from the component or overgrown whiskers.The component issue is bad. IF ANY of a batch of components has any impurities or corrosion in their leads,over time there is a major chemical reaction event, resulting in powdered crumbling coagulated goo !!Lead free in electronics was a bad decision, considering the amount it represents. All they had to do wasinstigate a better recycling system. They haven't worried about the amount of lead in car batteries or manyother products .. and what about now extra mercury in "energy" friendly globes. What a mess.

author: ivan747
author_rank: Super Contributor
timestamp: July 23, 2012, 02:58:52 am
content: That's what happens when you get your priorities wrong.i can't think of many suitable replacements for SLA batteries, unless they manufacture automotive grade Li-Ions cheaply. Same style as the Volt or the Prius.

author: G7PSK
author_rank: Super Contributor
timestamp: July 23, 2012, 07:59:09 am
content: Most lead acid batteries in cars are changed by garages who will send them for recycling due to the scrap value same goes for cars that are sent to the scrap yard the first thing removed is usually the battery as it has a fairly high value for its size and mass.Whereas many domestic electronics were just dumped in the bin by their owners as having no value when they ceased to work or were replaced, rather than having the ROHS lead free regulations it is far better to have recycling laws as there are now in the UK and the rest of Europe, all manufactures and retailers of electronic goods have to accept back the old electronics for recycling there also has to be local authority recycling centers where all the old TV's computers etc. can be taken free of charge to the residents of the area for safe disposal.But perhaps the manufacturers of electronic goods like the failure due to tin whisker growth as long as it can be slowed down to take several years, like a thin coat of varnish on the boards which slowly vaporizes until whisker growth starts to penetrate.

author: EEMarc
author_rank: Regular Contributor
timestamp: July 23, 2012, 08:51:48 am
content: I wonder if clear enamel stops tin whiskers. It keeps moisture from condensing on pins and pads and causing problems.

author: DaveW
author_rank: Frequent Contributor
timestamp: July 23, 2012, 12:42:31 pm
content: Quote from: EEMarc on July 23, 2012, 08:51:48 amIt does help considerably, particularly the thicker coatings. Nasa have released another paper on this,http://nepp.nasa.gov/whisker/reference/tech_papers/2010-Panashchenko-IPC-Tin-Whisker.pdfFrom the paper, it looks like about a 2mil thickness stops them spreading. So a thick coat of parylene which will get under the parts nicely does make a difference in long term reliability

author: SeanB
author_rank: Super Contributor
timestamp: July 23, 2012, 03:39:40 pm
content: Lovely stuff parylene........ Hard to remove for rework, but you can solder through it if you have good cyanogen extraction. Would survive the chemical strip in the ultrasonic cleaner well, generally the board material would disintegrate before it did.

author: T4P
author_rank: Super Contributor
timestamp: July 23, 2012, 04:05:10 pm
content: Good luck getting that stuff under a BGAThat's why i say the people who support leadfree are batshit crazyI MEAN WTF, 60% of the world's lead are in military shells and what have you

author: saturation
author_rank: Super Contributor
timestamp: July 23, 2012, 04:25:51 pm
content: vivaT, thanks for the updated links. If you check the archives we chatted about wiskers some years ago, but it looks like things have not improved. The worst part is the expected reduction in reliability of consumer grade electronics.I didn't know the Toyota issue was related to tin wiskers,as officially Toyota and the US safety boards deny it.http://www.cnn.com/2012/07/12/us/toyota-acceleration/index.htmlhttp://www.huffingtonpost.com/2012/01/21/toyota-sudden-acceleration-tin-whiskers_n_1221076.html

author: free_electron
author_rank: Super Contributor
timestamp: July 23, 2012, 05:10:30 pm
content: Toyota was most likely tin whiskersEuropean union is of the principle : shoot : ready .. what is 'aiming' ? we need to translate that in 25 different languages first because we don't have a common one... sadly we spent all the money on the shot we fired, and the large banquet and after party when we signed off 'ready', so we can't hire a translator. ah well we did 2 out of 3 . close enough...I propose an immediate ban of lead in bullets, mortars, grenades and any other weaponry. Nobody tracks where it lands , nobody cleans it up afterwards and the temperatures during explosion evaporate it so it can be inhaled and scattered over a large surface.The military should be forced to clean up their 'litter'. There's more lead being distrubted by the military over a larger area than any other industry combined ( apart from car batteries maybe , but those are being traced and recycled to some extent.)Maybe theu can jump on her rocking-horses and file a proposal. They could slap a hefty fine for non compliance and wipe out the european debt with one invoice.

author: G7PSK
author_rank: Super Contributor
timestamp: July 23, 2012, 05:45:44 pm
content: Who was the idiot that decided that lead was safer travelling through the air at supersonic speed than lead lying quietly in circuit boards. Most likely a green activist that was also a member of the NRA.

author: Architect_1077
author_rank: Regular Contributor
timestamp: July 23, 2012, 05:57:11 pm
content: QuoteThere, fixed for ya

author: Unknown
author_rank: Unknown
timestamp: July 23, 2012, 05:59:45 pm
content: Thanks for the eye opener guys. Now I think important proportion of electronic waste is precisely due to its being lead free.Millions of computers and phones dumped into land fills due to tin whiskers..

author: M. András
author_rank: Super Contributor
timestamp: July 23, 2012, 06:06:56 pm
content: do you have to complie for that rohs bullshit if you want to markt a product which was made with the standard lead+tin solder?

author: slateraptor
author_rank: Frequent Contributor
timestamp: July 23, 2012, 06:16:42 pm
content: Quote from: free_electron on July 23, 2012, 05:10:30 pmMany indoor shooting ranges implement back drops that collect expended bullets which are periodically emptied and sold to scrap yards. It's to my understanding that indoor ventilation systems are a must, but I suspect this is largely driven by air quality in general rather than any direct threat caused by lead vapor.The US military implements certain measures to aid in minimizing waste, e.g. the use of "laser tag" systems for combat training. In the end, however, there's no substitute for training with the real thing. Most people probably don't know that training ammunition used by military and law enforcement are manufactured largely from recycled materials, i.e. reformed brass and bullets cast from recycled scrap. On a similar note, Air Force bases are assigned officers in charge of managing affairs like hazmat, precious metals reclamation and operations environmental impact. And these are just the things that I'm personally familiar with.Quote from: Architect_1077 on July 23, 2012, 05:57:11 pmP.S. I'm a card-carrying NRA member. =\

author: slateraptor
author_rank: Frequent Contributor
timestamp: July 23, 2012, 06:24:16 pm
content: Quote from: G7PSK on July 23, 2012, 05:45:44 pmEvidently, the same idiot who thought it safe to circulate household water in lead pipes. =\

author: M. András
author_rank: Super Contributor
timestamp: July 23, 2012, 08:19:49 pm
content: just read trough that nasa paper, seriously they cant show these results to those eco nuts? i would ask those idiots, hey dud what would yo do when your tv or computer dies cos of your stupidity? even they luxury cars with the extensive onboard computer. if they cant find the problem of the whiskers, or cease them effectively they should ban the pure tin from every segment of manufacturing. not to develop expensive ineffective measures. electronics industry had no problem with the tin+lead solder for decades, with the leadfree shit they had problems in the very beginning

author: vivaT
author_rank: Contributor
timestamp: July 23, 2012, 10:47:41 pm
content: Im glad to hear about your experiences and previous discussions, it certianly has been a topic which personally ive been avoiding and im sure a lot of other people just reach for the 60/40 old faithful stuff since leadfree came in.At least one thing is for sure the repair industry could get a boost, combined with our ecomeny you've got a doublewhammy that can help people return to the old ways of saving things instead of recycling.My slogan is now Repair, not recycle!

author: AntiProtonBoy
author_rank: Frequent Contributor
timestamp: July 24, 2012, 01:48:36 am
content: I throw a kilo worth of lead into the sea each year via fishing alone.

author: dbinokc
author_rank: Contributor
timestamp: July 24, 2012, 01:59:31 am
content: I do not know about the accelerator problems, but there were Toyota engine control units that had the tin whisker problem because of an improperly applied conformal coating. I learned first hand, when my 07 Corolla suddenly stopped running while going down the road. There was a recall on the ECU's and it was replaced for free.Quote from: saturation on July 23, 2012, 04:25:51 pm

author: SeanB
author_rank: Super Contributor
timestamp: July 24, 2012, 04:50:01 am
content: Spark plugs are more environmentally friendly, and are cheap/free from a garage, provided the staff have not scooped them for themselves.

author: DaveW
author_rank: Frequent Contributor
timestamp: July 24, 2012, 07:50:09 am
content: Quote from: DaveXRT on July 23, 2012, 04:05:10 pmParylene will go right underneath a BGA. Although when you see some of these 8mm long whiskers-terrifying what the effect of those would be underneath a fine pitch component.I'd love to know what studies they actually looked at, if any, before deciding on this. The effect on reliability seemed to be known to some extent, especially given all the exemptions. Although even for us in industries with exemptions, we're stuck with COTS parts that all come lead free compatible anyway

author: T4P
author_rank: Super Contributor
timestamp: July 24, 2012, 01:51:55 pm
content: Doesn't mean it's no good for SnPb.I'm gonna show this to my dickhead of a lecturer and give him a headache*he claimed environmental, that was before i knew 60% of lead is in the air ( weapons )

author: Architect_1077
author_rank: Regular Contributor
timestamp: July 24, 2012, 01:59:11 pm
content: QuoteNo pun intended against the NRA or its members. I was merely adding to the joke against the environmentalists/arguments that favor the use of lead-free solder.

author: Architect_1077
author_rank: Regular Contributor
timestamp: July 24, 2012, 02:01:52 pm
content: Quote from: AntiProtonBoy on July 24, 2012, 01:48:36 amLOL

author: Hypernova
author_rank: Unknown
timestamp: July 24, 2012, 02:17:45 pm
content: What really scares me is that despite the seriousness of this phenomenon nobody has a fucking clue how it really works.

author: tom66
author_rank: Super Contributor
timestamp: July 24, 2012, 02:38:30 pm
content: Due to increased lead free failures, this is more likely to do more damage to the environment than leaded solder ever did.I'm all for keeping waste out of the environment but by far the best way to do this is to build reliable electronics that do not need to be thrown away and encourage people to buy and sell second hand electronics instead of disposing of perfectly functional pieces. If they do decide to dispose of it then it needs to be managed, WEEE tries but doesn't really do the job.

author: jerry507
author_rank: Regular Contributor
timestamp: July 24, 2012, 06:50:49 pm
content: What exactly are the increased lead free failures? The Toyota issue is the only specific example stated in this thread, yet there seems to be a perception that lead free solder has contributed to the increased failure of electronics these days. Is there actually any data to back this perception up? The Toyota problems were very early on, every new technology is bound to have growing pains.

author: SeanB
author_rank: Super Contributor
timestamp: July 24, 2012, 06:55:47 pm
content: Nokia bricks from before ROHS still work after many years, you just need new batteries. Newer phones die for no reason after a few years.

author: T4P
author_rank: Super Contributor
timestamp: July 24, 2012, 07:26:36 pm
content: Quote from: jerry507 on July 24, 2012, 06:50:49 pmIt's the fact dude.Manufacturers earn from lead free solder, at first they were worried about product sudden death but now they aren't,because all they want is built-in obsolescence

author: Neganur
author_rank: Unknown
timestamp: July 25, 2012, 12:39:47 pm
content: Quote from: free_electron on July 23, 2012, 05:10:30 pmoh come on ...

author: Bored@Work
author_rank: Super Contributor
timestamp: July 25, 2012, 05:25:46 pm
content: Quote from: free_electron on July 23, 2012, 05:10:30 pmBy your own statements you have left Europe a long time ago and have no plans to ever come back. So why do you think it is any of your business any more?QuoteVery good idea. Especially if it comes to depleted uranium, landmines and other shit.

author: jerry507
author_rank: Regular Contributor
timestamp: July 25, 2012, 05:36:48 pm
content: Quote from: DaveXRT on July 24, 2012, 07:26:36 pmWe went from linking NASA studies to simply declaring things as facts. I'm not saying anything one way or another, I simply wanted to know if there was any sort of data on long term stability of lead free solder. Electronics manufacturing has suffered from a lot of different quality issues in the last 10 years, so simply saying "stuff breaks more often" doesn't provide significant evidence that lead free solder isn't long term stable.And some mitigation efforts such as conformal coating are certainly not bad things. If only MORE products conformal coated...

author: Unknown
author_rank: Unknown
timestamp: July 25, 2012, 06:05:23 pm
content: Here is what I just found inside an erratically behaving mouse. I repaired the cable on this one several times to no avail. Having noticed and cleaned more severe "white fuzziness" before I decided to open it again and take some pictures. The label says RoHS compliant and the solder feels distinctly lead free under the soldering iron. Not having better magnification I am unable to say anything conclusively but you can draw your own conclusions.

author: jerry507
author_rank: Regular Contributor
timestamp: July 30, 2012, 03:52:40 pm
content: Quote from: HAL-42b on July 25, 2012, 06:05:23 pmVery interesting! It seems strange to me that there would be tin whiskers coming through the solder mask. Is there no conformal coating? It doesn't look like it...

author: Unknown
author_rank: Unknown
timestamp: July 30, 2012, 07:50:47 pm
content: Quote from: jerry507 on July 30, 2012, 03:52:40 pmNo conformal coating. Just solder mask.

author: nitro2k01
author_rank: Frequent Contributor
timestamp: July 31, 2012, 02:27:16 am
content: Quote from: jerry507 on July 30, 2012, 03:52:40 pmIn terms of force required to penetrate the mask, whiskers could grow through a layer of solder mask, for sure. (Based on the NASA paper.) The stranger part is if the copper is tinned under the solder mask.If the ones marked with a question mark are indeed tin whiskers, they've likely grown out of the joint and then come loose. Did you try analyzing them anything? Such as picking one up with a pair of tweezers at one of the ends, and heating the other end with a hot soldering iron. And just for clarification, are the things in the picture placed above or below the solder mask?

author: dcel
author_rank: Regular Contributor
timestamp: July 31, 2012, 07:24:22 am
content: LCD monitor up and quits while I'm using it. Pull out the PSU/inverter board, go across the street to TV shop, owner has ESR cap checker to work on all the TVs with. All caps check out good. Take PSU back home and decide to vacuum the dust off so I can start trouble shooting the thing, plug everything back in and it works, um? Start looking really close and there is "fuzz" on few of the solder joints on an adjacent board, so I vacuum everything off and its been working since, I'm using it now. This is not the first thing that has been mysteriously "repaired" by just a through cleaning. Talked to TV shop owner next day about it and he said that allot of the repairs he does are either a good cleaning, which he does first, or the usual PSU caps. Now I can't say for sure that tin whiskers are to blame here, but it makes you think.Chris

author: Unknown
author_rank: Unknown
timestamp: July 31, 2012, 07:54:20 am
content: Quote from: nitro2k01 on July 31, 2012, 02:27:16 amThe board is solder coated.edit: No it is not. Just normal solder resist and tinningNo copper is visible.I tried handling the black whiskers with the tiniest tweezers that I have to no avail. As soon as I touch them they fly off and disappear. Just like when cutting steel wire with side cutters - they fly across the room never to be seen again.The white ones are a little bit more resilient but still no success trying to remove one and study it separately.Anyway, I cleaned the board thoroughly with IPA and a plastic brush. If those were whiskers they should grow back.

author: ejeffrey
author_rank: Super Contributor
timestamp: July 31, 2012, 09:52:16 am
content: It is definitely not normal to have a tin plating under the solder mask. The tin coating is applied after the solder mask and only coats the exposed copper pads. This is easy to test, just scrape away the solder mask somewhere and you will see reveal uncoated copper. I strongly suspect that any tin whiskers you see in the solder mask came from one of the solder joints and broke off.

author: Unknown
author_rank: Unknown
timestamp: July 31, 2012, 11:22:35 am
content: Quote from: ejeffrey on July 31, 2012, 09:52:16 amYou are correct. I opened it up again and scraped away the resist. There is no tin coating there. So those black things are probably not tin whiskers.BTW the mouse was thoroughly cleaned and stayed connected to 5V for around 24 hours. There is no visible regrowth of whiskers (if they were whiskers in the first place) I will leave it connected for a month or so and check again.