So what's the truth about lead-free solder ?

[Jan Panteltje]

What was the chipcode dates on that DAB ?
No more than 2 years old no doubt.

If you had not repaired it than also no doubt it would have ended in
landfill taking with it ,perhaps not lead, but antimony, bismuth, tin,
copper, barium , phthalates etc

Actually, in the long ago past when I had the TV repair shop, I had exactly
the same problem on old tube connectors in PCBs and also on inductiors, and old
Philips K8 connectors, some after 2 years too I think.
With leaded solder.
This is also also an issue of better connections, some that allow some movement,
like WIRES for example...
I mean use flexible wires to connect the hot components to a PCB.
That defeats the idea of PCB perhaps.
But I only wanted to point out that that thermal effect is also present in leaded
solder.
It could be worse in leadfree, but you'd have to test in the same setup.
He *could* have resoldered one with 60/40 and when it comes back in 2 years
see which ones gave way ;-)




workin gas TV repair

 

[Eeyore]

Actually, in the long ago past when I had the TV repair shop, I had exactly
the same problem on old tube connectors in PCBs and also on inductiors, and old
Philips K8 connectors, some after 2 years too I think.
With leaded solder.

The temperature cycles would have been rather higher methinks.

Graham

 

[Eeyore]

He *could* have resoldered one with 60/40

No, that's illegal per the rules from the idiots in Brussels. It could result in a
fine of £2000.

Graham

 

[Glen Walpert]

The debate about lead free solders seem to be nearly as politically charged as
that about anthropogenic global warming and a casualty seems to be useful data.

I've read plenty of comments to the effect that lead-free is less reliable in
the long term (vibration seems to be a key weakness AIUI - maybe also thermal
cycling) which presumably explains the exemptions for certain categories, yet
I've also seen some studies that claim it can out-perform lead containing
solders.

Is there any real hard and fast information out there that one can rely on ?

Graham

Don't look to this newsgroup for factual info on lead free! Instead
look at actual test results in the trade publications such as SMT
magazine:
http://smt.pennnet.com/home.cfm
They have published numerous tests comparing various lead free
materials and processes with tin-lead. Some lead free materials and
processes are better than others (no surprise) and picking the best
one for your situation is non-trivial.

My nutshell summary of the published test results is that lead free is
significantly harder to do right than tin-lead, requiring tighter
process controls, but if done right it can be more reliable than
tin-lead for non-shock situations. Lead free is harder, stronger and
more brittle than tin-lead so tin-lead will deform plastically under
high shock when lead free will break, however lead free will withstand
more hot-cold cycles than before failure than tin-lead (better fatigue
resistance). So you need to know what the significant failure
mechanisms are in your design to pick the most reliable materials.

Glen

 

[Guy Macon]

reprocessing lead, and lead alloys is far easier and less
costly than mining it.

So all those owners of lead mines are wasting all that
money doing things the more expensive way as a public
service?

 

[mpm]

Follow the derogations/exemptions.
Military , aerospace & medical do have derogation from WEEE and RoSH, but
can anyone nail down precisely why they are exempted.

I suspect it is because these fields are considered "life-safety"
fields.
Even ordinance, when you think of it in terms of friendly fire
incidents.
They probably just don't want to recertify their processes, or don't
have the time to do it right.

But the "Truth"?
That's much more elusive.
Does RoHS result in a better environment? I don't know, but I doubt
it.
The sheer number of TV sets that will be obsoleted in the coming years
due to the migration to Digital Television will probably swamp the
RoHS "gains" by orders of magnitude.

Ditto for the batteries used in some electric cars, and the US's
(likely?) ultimate reliance on it's vast coal reserves to power all
this crap. And that's if Global Warming doesn't get us first...

Bottom line: I don't think the environment gives a sh^t about RoHS,
or WEEE.
I think we need fewer people, and less "disposable" crap from China.

-mpm

 

[Jan Panteltje]

I suspect it is because these fields are considered "life-safety"
fields.
Even ordinance, when you think of it in terms of friendly fire
incidents.
They probably just don't want to recertify their processes, or don't
have the time to do it right.

But the "Truth"?
That's much more elusive.
Does RoHS result in a better environment? I don't know, but I doubt
it.
The sheer number of TV sets that will be obsoleted in the coming years
due to the migration to Digital Television will probably swamp the
RoHS "gains" by orders of magnitude.

Right, I turned in a portable TV last week.
This one was about 30 years old (seventies), and was still working OK,
but no analog transmissions here anymore, all you get is nice equal
distributed noise when tuning in to a digital station.

 

[Joe Chisolm]

The debate about lead free solders seem to be nearly as politically
charged as that about anthropogenic global warming and a casualty seems to
be useful data.

I've read plenty of comments to the effect that lead-free is less reliable
in the long term (vibration seems to be a key weakness AIUI - maybe also
thermal cycling) which presumably explains the exemptions for certain
categories, yet I've also seen some studies that claim it can out-perform
lead containing solders.

Is there any real hard and fast information out there that one can rely on
?

Graham

Dr Howard Johnson (High Speed Digital Design) had this article in
his email newsletter (and posted on his site). Interesting read.
Rollback RoHS: http://www.sigcon.com/Pubs/news/10_01.htm

 

[Jan Panteltje]

Dr Howard Johnson (High Speed Digital Design) had this article in
his email newsletter (and posted on his site). Interesting read.
Rollback RoHS: http://www.sigcon.com/Pubs/news/10_01.htm

Well seems [all] we have to [do is] make some traces .65mm apart

 

[Traver]

The main issue for lead free in military and aerospace electronics is
tin whiskers. Tin solder will
grow conductive whiskers that even penetrate conformal coatings. In
low power circuit,
the whisker will short something out. In a high power circuit, it
might burn up like a fuse,
but if it happens in a satellite (no atmospheric pressure) the little
whisker will cause
a plasma arc capable of passing huge amounts of current.

We in the defense electonics industry fight with this issue every day
and the information
is very confusing. Parts turn lead free midstream in production and
seems impossible to
keep tack of it. Every company is dealing with it differently. We stay
away from certain
finishes like bright tin and look at the spacing of components and
coatings on our boards.
This can mitigate some of the reliability risks of lead free.

If high-rel is of upmost importance, we struggle to find tin-lead
parts.

 

[Eeyore]

Joe Chisolm wrote

Dr Howard Johnson (High Speed Digital Design) had this article in
his email newsletter (and posted on his site). Interesting read.
Rollback RoHS: http://www.sigcon.com/Pubs/news/10_01.htm

Well seems [all] we have to [do is] make some traces .65mm apart

Some ? ALL !

Goodbye microelectronics.

I just came across this too.
http://en.wikipedia.org/wiki/Tin_pest

" At 13.2 degrees Celsius (about 56 degrees Fahrenheit) and below, pure tin
transforms from the (silvery, ductile) allotrope of beta-modification white tin
to brittle, alpha-modification grey tin. Eventually it decomposes into powder,
hence the name tin pest."


Graham

 

[Allodoxaphobia]

The debate about lead free solders seem to be nearly as politically charged as
that about anthropogenic global warming and a casualty seems to be useful data.

More than political -- the subject could easily be viewed as troll bait.
It's been 'discussed' many times in ser.

http://tinyurl.com/22c6t

 

[Spehro Pefhany]

Joe Chisolm wrote

Dr Howard Johnson (High Speed Digital Design) had this article in
his email newsletter (and posted on his site). Interesting read.
Rollback RoHS: http://www.sigcon.com/Pubs/news/10_01.htm

Well seems [all] we have to [do is] make some traces .65mm apart

Some ? ALL !

AFAIK this exemption only applies to component lead finishes.

Best regards,
Spehro Pefhany

 

[Jan Panteltje]

Joe Chisolm wrote

Dr Howard Johnson (High Speed Digital Design) had this article in
his email newsletter (and posted on his site). Interesting read.
Rollback RoHS: http://www.sigcon.com/Pubs/news/10_01.htm

Well seems [all] we have to [do is] make some traces .65mm apart

Some ? ALL !

AFAIK this exemption only applies to component lead finishes.

Best regards,
Spehro Pefhany

Too bad....
How about conductive glue replacing solder?
Na, will have to wait until the first EU politician's cellphone fails in
some emergency.

 

[Eeyore]

More than political -- the subject could easily be viewed as troll bait.
It's been 'discussed' many times in ser.

It's not a troll.

New data ought be available as to the effects on actual in-service reliability of
lead-free by now. It seems as I expected, anecdotally, that musical equipment
products that tend to see high levels of vibration are suffering.

Graham

 

[msg]

Jan Panteltje wrote:

How about conductive glue replacing solder?
Na, will have to wait until the first EU politician's cellphone fails in
some emergency.

What ever happened to 'multiwire' (or some such trade name)? It was
a multilayered weld-bonded wiring alternative to multilayer PCBs
in the '60s and '70s and was very rugged, easily implemented with
NC technology, and used no solder of course.

Since each layer is built up in succession, between power and ground
planes, even BGAs can be accomodated.

Regards,

Michael

 

[Eeyore]

How about conductive glue replacing solder?

How about getting a clue ? You can get conductive epoxy adhesive btw. It's
loaded with silver particles and is ridiculously expensive.

Graham

 

[Eeyore]

Jan Panteltje wrote:



What ever happened to 'multiwire' (or some such trade name)? It was
a multilayered weld-bonded wiring alternative to multilayer PCBs
in the '60s and '70s and was very rugged, easily implemented with
NC technology, and used no solder of course.

Gone the same way as wire wrap it seems.

Graham

 

[Alex]

I reworked all the joints with lead-free, as that is what the RoHS

legislation legally charges me to do as a commercial repair outfit, but boy,
the temptation was strong to just reach for the leaded solder, and do the
job 'properly' ...

If you use leadfree solder, remember that the temperature is a bit
higher, and this makes the fumes from resin much more dangerous to
YOU..
Second.. if the components is made for leadfree solder , it can happen
that the tin/lead solder wont make a good solder-joint. ( but I agree
that sometimes one is tempted )
Alex

 

[Eeyore]

Second.. if the components is made for leadfree solder , it can happen
that the tin/lead solder wont make a good solder-joint.

No, that's not true AIUI. It's the other way round.

Graham