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Re: lead free solder again


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so I
is

Given the diameter of the whiskers, I doubt if they develop enough
force to punch through. Strange phenomena anyway, because the whiskers
don't start everywhere, but just here and there.


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That's the one and only I heard off, and was mentioned here at
SED about a month ago? One case is not much. I don't hear Philips,
Sony, JVC, Samsung, HP, Canon, etc.

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implications

The list of exemptions can be widened, if need be. I can imagine
they add wrist watches to the list of exemptions, not much solder
in a wrist watch anyway, so who would care about that kind of
stuff being lead-free or not.

--
Thanks, Frank.
(remove 'q' and '.invalid' when replying by email)








Re: lead free solder again



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The big companies you mention are absolutely delighted that "through no
fault of their own" their products will have very short lifetimes, the
intermittent nature of lead free solder failure has created a consumer
mindset that once an item fails it will continue to give nothing but trouble
no matter how competently repaired, so most equipment is thrown out at the
first hint of intermittent operation!!!



Re: lead free solder again




ian field wrote:

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Which is of course about as *ungreen* as it gets despite the apparent motive
behind RoHS !

Graham



Re: lead free solder again



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Re: lead free solder again


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trouble
the
motive

Somehow I just don't believe you're complaining because of the environmental
issues. Are you sure its got nothing to do with the hassles it gives, or
with
the fear for the unknown?

Let's see what happens. If it turns out as a disaster, nothing to worry.
We're all in the same boat. If it can't be solved, we'll be back to
leaded solder in notime.

BTW, I don't like lead-free either, it doesn't solder as nicely as the
good old leaded stuff. But it doesn't upset me, and my prototype stuff
and bench experiments don't suffer either.

--
Thanks, Frank.
(remove 'q' and '.invalid' when replying by email)



Re: lead free solder again


Hello Frank,

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Ahem, couldn't it be the fear of the known? What telco companies found
out in the 40's can't simply be legislated away. Except that some
Eurocrats think they could. When you have a known problem and find a
solution (adding lead in this case) you typically don't go back to the
old stuff sixty years later without significant and proven mitigation.
Well, guess in Brussels they do that...


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With all due respect, I believe that position is a wee bit naive. Or
like they say in France, laissez faire. No worry, be happy, KABOOM.


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And, of course, there will be no unintended consequences such as legacy
RoHS equipment that is going to be in use and where nobody knows when
and how spectacular the failure will be, will there?


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Prototype stuff is fine. We'll all learn how to handle lead-free. The
problems may or may not surface after a few years. But when they do
surface, boy, I don't want to be the VP of Quality Control at one of the
manufacturers.

--
Regards, Joerg

http://www.analogconsultants.com

Re: lead free solder again


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Adding lead turned out to be a problem as well, so it was only
a half baked solution. Removing the lead in our car fuel was
not a bad idea. The 40% percent lead in solder is a *lot* and
seems worth looking into. Not at all costs/risks, so there are
a couple of exemptions already made.


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Au contraire, the wasted lead is the ticking time bomb.

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Ah, it *is* fear of the unknown ;)

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All the VP's of QC are in the same boat as well. They all earn shitloads
of money and can retire at 40.

--
Thanks, Frank.
(remove 'q' and '.invalid' when replying by email)




Re: lead free solder again


Hello Frank,

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Half baked? It worked. In cars it was easier, basically better valve
seats. My 1969 Citroen (engine designed in the late 30's or so) was
quite modern in that respect. It had no problems with unleaded.

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Nothing to worry? We'll watch that from a safe distance :-)

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Note that I didn't say "if" but "when" and "how spectacular". Just wait
until a couple of pins on the uC of a gas furnace controller let go
because the solder joints fouled up.

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Not around here, at least not for small companies. Small companies tend
to be less politically connected and that can burn then when RoHS does
backfire.

--
Regards, Joerg

http://www.analogconsultants.com

Re: lead free solder again


Hello Joerg,

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Well, this is true, but RoHS is not the only case where this is true.
How many spectacular failures are to come, due to crappy but cheap
components, moving production to China, which causes reliability
problems both due to low poduction quality and swamping the world market
with counterfeit parts. The latter is for maximizing someone's profit,
RoHS at least has a more appealing motive.


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I don't think you can safely say "when", "if" is still appropiate. Tin
whiskers are far from being understood, it is believed that tin/lead
solder is a remedy for them. I agree that RoHS is a large scale
experiment, but an experiment with unknown result.
With regard to your gas furnace controller: no mission critical system
must blow up, just because a solder joint fouled up. Defective solder
joints were also a common problem in leaded times :-)

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Don't know, most consumer products are nowadays anyway products with a
life time of less than a few years. RoHS is mostly directed to this
market. Personally I don't think it will change much there. The end user
doesn't care whether his/her gadget stopped working because a tin
whisker appeared or an undersized and overheated capacitor just shorted
  out. Finally, I don't think there are many VPs of Quality Control left
in  the consumer business anyway. Most of it looks as if everything
which comes from the assembly line is shipped without even a simple
on/off test.

Klaus

Re: lead free solder again


Hello Klaus,

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With one BIG difference: RoHS is government mandated, going to China is
every company's choice.

BTW, some of my designs are produced in China. A few of them since more
than a decade. No problems and excellent quality. You must select a
proper facility to contract with, just like in every other country.

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You just said it: "...it is believed...". Eurocrats probably have no
clue what they just brought upon mankind. Time will tell. When it goes
wrong I guess they'll have their fat taxpayer funded retirement benefits
and no worries.


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The chance of that happening will increase with a decreasing quality or
durability of solder joints. Worst case an accident happens, best case
the thing quits when it's below zero and some pipes freeze and burst.


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Not the ones I buy.


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They, or organizations such as Consumer Affairs, will rather quickly
figure out what lasts and what doesn't. In the same way they did with
cars. There are certains brands I and others will not buy. We also pay
close attention to where something is assembled and prefer merchandise
from one area over others.


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Every company I design for has a full quality control system. Else I
wouldn't design for them. Yes, there are some consumer products where I
have the impression that they are shipped "as is". I buy from those
companies exactly once, if that, and then never again.

--
Regards, Joerg

http://www.analogconsultants.com

Re: lead free solder again


Hello Joerg,

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I don't see the big difference. Marketforces dictate going to China.
Once consumers find out, that the cheap buy in the long run wasn't so
cheap anyway, the company sticking to quality products is likely out of
business. Both cases are in my point of view external forces one has to
react to. Not going to China is like chosing not to sell in the EU -
same degree of freedom.

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While I certainly agree on that it is possible to produce good products
in China, I'd still say, that on average it has become harder to find
decent electronics products, especially in the consumer product scene.
Moving the production to China is perhaps not the cause but only the
symptom for the general tendency that the end user price has become the
singular criterion for sales success.

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This probably holds also for the CEO's etc. ruining a good company for
their and their stakeholders short term profit - I'm thinking of Enron
or the downturn of HP for example...
Without wanting to start a political discussion, I have to add the
statement, that according to democratic theory the so called Eurocrats
are doing what people want them to do. Hence, it is the European people
  bringing RoHS on mankind. I'm not saying that it will go without
problems (no none knows yet), but again they are doing what they are
expected to do and have hence "earned" their retirement benefits - at
least according to theory :-)


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True. I'm not saying that life becomes easier, but I think it is the
engineering task to adapt to new challenges, which in this case means
one has to handle RoHS on a technical level. If RoHS imposes higher risk
of failure one has to take countermeasures. Makes things more
complicated and more expensive, but again this is a foreseeable
challenge, it would be bad engineering to design and produce electronics
as we always did and then blaming "Eurocrats" for the failure of our
products. The information is available for years.

Klaus


Re: lead free solder again


Hello,


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Nobody forces anyone to go to China. Very different from RoHS. In fact,
why do you think that Japanese cars for the US market are still
manufactured in Japan or at very tightly controlled US factories? Both
are high-wage countries and the cars cost substantially more than models
produced in low-wage countries. Are those companies going out of
business? Au contraire, they are enjoying the best profits of them all.
Other companies that did outsource aren't faring that well. The consumer
hath spoken.


Not going to China is like chosing not to sell in the EU -
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Absolutely not. The EU has placed a legislative roadblock in the way.
Except that this time it will likely backfire.

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ROFL! Almost spilled my glass of water here ... you don't seriously
believe that, do you?

Democratic theory, yes. Reality, no. Just follow the discussions that
happened in some of the European usenet forums.

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It may be too late by then. When failures in installed gear reach
epidemic proportions you'll have a whole lot of unhappy campers. While
they may now be oblivious then they'll want to know who dunnit.


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Like, where?

--
Regards, Joerg

http://www.analogconsultants.com

Re: lead free solder again


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I think a good entry point is:

Galyon, G.T., "Annotated tin whisker bibliography and anthology", IEEE
Trans. Electronics Packaging Manufacturing, Vol. 28, Iss. 1, 94-122

A very useful overview article with an almost complete list of ~100
references.

Klaus



Re: lead free solder again


Hello Klaus,


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Ok, thanks. Got that paper now but will have to study a little later
since I just received a box of prototypes for debug. Full of 0402, not
exactly fun. Luckily assembled on a non-RoHS line so no whiskers ;-)

--
Regards, Joerg

http://www.analogconsultants.com

Re: lead free solder again


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I like this historical summary:
http://thor.inemi.org/webdownload/newsroom/Presentations/SMTAI-04_tin_whiskers.pdf

Re: lead free solder again


Hello John,

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http://thor.inemi.org/webdownload/newsroom/Presentations/SMTAI-04_tin_whiskers.pdf
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That's pretty much the article Klaus pointed out. Not what I was looking
for though.

--
Regards, Joerg

http://www.analogconsultants.com

Re: lead free solder again


Hello Klaus,


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Ok, that wasn't really the kind of paper I was looking for. I could dig
through the 100+ references now. However, from a responsible legislative
body I would have expected at least something like a watertight
scientific long term test. Such as "Hey, we have soldered these boards.
This is how we did it and these are the materials and temperature
profiles. We then exposed them to various climate conditions for 15
years and here are the quality results".

--
Regards, Joerg

http://www.analogconsultants.com

Re: lead free solder again



Joerg wrote:
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  According to the NASA site
(http://nepp.nasa.gov/whisker/background/index.htm#q6 ), 3% Pb is enough
to dramatically reduce whisker formation:

"Studies have shown that alloying tin with a second metal reduces the
propensity for whisker growth. Alloys of tin and lead are generally
considered to be acceptable where the alloy contains a minimum of 3%
lead by weight. Although some experimenters have reported whisker
growth from tin-lead alloys, such whiskers have also been reported to
be dramatically smaller..."

  So, why don't the Euro-folks just limit solder to 3-4% Pb as a first,
safe step?  That's a 10-fold reduction.  Total Pb might be reduced over
RoHS, as more devices might be included, and longer-lived consumer
devices would be an environmental win too.

  Curiously,
  James Arthur

(Alternatively, you could outlaw FR-4, epoxy, ...etc.  In California
they're considered hazardous waste.

   It's all very strange.  Hydrogenated fats kill far more people, and
they're added to food deliberately.)


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Because the precautionary principle deems that you can't have too little of
a bad thing.

--

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That's what one woman, IIRC in Scotland, thought and vigorously shielded
herself from any and all germs, bacteria and whatnot.

AFAIR she died from a simple cold.

--
Regards, Joerg

http://www.analogconsultants.com

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