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Tin whiskers: What happens when they spontaneously erupt? (2018)

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Re: Tin whiskers: What happens when they spontaneously erupt? (2018)

#101

Post by coryrc »

Animats wrote: post #86
Animats wrote: post #57

Earlier quoted context omitted.

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 commonl…

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 o…

Low-temp aluminum brazing rod has cadmium.

Re: Tin whiskers: What happens when they spontaneously erupt? (2018)

#102

Post by trhway »

foldr wrote: post #98
trhway wrote: post #96

Earlier quoted context omitted.

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. progr…

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 vacuuming up every last spec…

During 6 and 7 grade i was at electronics hobby club where beside soldering of new stuff we also did a bunch of desoldering too as the main source of electronics components where the PCBs pulled out from the pieces of missiles/torpedoes/etc at the Navy dumps. There was no any "safe handling" procedures wrt. lead. Granted though that washing hands before eating has been ingrained in me (and as far as i saw - in my friends too) from the early childhood.

Don't get me wrong - I'm not arguing about un-safety of lead. I'm just wondering how things can be different when one knows vs. when one doesn't know. Statistically speaking a bunch of people i knew though the childhood/school should have some lead damage. Many of them went to become military/Navy officers (growing on a Navy base biases your choice that way, i also did an attempt to go to military officers college). As my childhood was pretty typical for that time in USSR, I wonder what systemic effect missing few IQ points by a large number of people can have.

Re: Tin whiskers: What happens when they spontaneously erupt? (2018)

#103

Post by foldr »

trhway wrote: post #102
foldr wrote: post #98

Earlier quoted context omitted.

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 vacuuming up every last spec…

During 6 and 7 grade i was at electronics hobby club where beside soldering of new stuff we also did a bunch of desoldering too as the main source of electronics components where the PCBs pulled out from the pieces of missiles/torpedoes/etc at the Navy dumps. There was no any "safe handling" procedures wrt. lead. Granted though that washing hands before eating has been ingrained in me (and as far as i saw - in my fri…

I'm not quite sure what your point is. Of course we know that people can do lots of soldering using leaded solder and not suffer any obvious harm. It's not an enormously risky activity. It just seems pointless to take the risk when you don't have to.

Re: Tin whiskers: What happens when they spontaneously erupt? (2018)

#104

Post by tinco »

atesti wrote: post #99

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

When did that happen? I bought a spool just over a year ago and the sales person didn't bat an eye. This was in The Netherlands, if we don't have the same law then maybe there's your answer?

Re: Tin whiskers: What happens when they spontaneously erupt? (2018)

#105

Post by moltke »

oceanplexian wrote: post #84
squarefoot wrote: post #66

Earlier quoted context omitted.

> Consumer electronics used to break down all the time 50 years ago But they could be easily repaired.

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.

My understanding is that the new manufacturing techniques stop many people but usually not skilled technicians. It's component serialization, keeping schematics secret, and exclusive supply chains that are the real problem.

Re: Tin whiskers: What happens when they spontaneously erupt? (2018)

#106

Post by at_a_remove »

kimixa wrote: post #93
at_a_remove wrote: post #47

Earlier quoted context omitted.

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.

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…

That first question, it is 100C at STP. Second question, enough to make you have a second or third degree burn. Third question, yes.

Re: Tin whiskers: What happens when they spontaneously erupt? (2018)

#107

Post by ericbarrett »

squarefoot wrote: post #66
zozbot234 wrote: post #54

Earlier quoted context omitted.

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.

> Consumer electronics used to break down all the time 50 years ago But they could be easily repaired.

My mid-1980s digital alarm clock came with a full schematic. Can you imagine that today?

Re: Tin whiskers: What happens when they spontaneously erupt? (2018)

#108

Post by robomartin »

xmodem wrote: post #38
robomartin wrote: post #9

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 pok…

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)

> will a device that's in constant use develop them faster than a physically identical device that's switched off and in storage

Storage was one of the areas I researched extensively. It was like that scene in the movie "Clear and Present Danger" [0] in that the answer was always the same frustrating one regardless of conditions:

Stochastic growth onset; 0 to 3 years; can't predict growth start or rate; can't stop them; they will penetrate almost anything practical you can put on a board.

[0] https://www.youtube.com/watch?v=PqtjbWJPIgQ

Re: Tin whiskers: What happens when they spontaneously erupt? (2018)

#109

Post by pomian »

walrus01 wrote: post #78
Damogran6 wrote: post #31

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…

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…

Raised floors where a great way to create laminar flow for clean rooms. I suspect that as with manufacturing, the "clean" space is inside the computers now.

Re: Tin whiskers: What happens when they spontaneously erupt? (2018)

#110

Post by zozbot234 »

ericbarrett wrote: post #107
squarefoot wrote: post #66

Earlier quoted context omitted.

> Consumer electronics used to break down all the time 50 years ago But they could be easily repaired.

My mid-1980s digital alarm clock came with a full schematic. Can you imagine that today?

Actually, yes I could imagine that quite easily. Just buy "hackable" products which do that as a matter of course. A digital multi-purpose device with an alarm-clock form factor would not even be especially complicated to make.
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