N_Cook said:
and some balancing comment
http://www.guardian.co.uk/technology/2008/apr/24/2
# The Guardian,
# Thursday April 24 2008
A whisker of doubt
I believe there are several inaccuracies in Kurt Jacobsen's article
(Within
a whisker of failure, April 3). He cites the Swatch watch company as
recalling a "huge batch" of watches that amounted to a financial loss,
when
in fact Swatch was denied its request for a RoHS exemption, as another
supplier makes lead-free quartz movements it could use with no whisker
issues. Also, Swatch makes no mention of a recall in its EU request. The
nuclear power plant failure example and others are also misleading, as
these
were failures due to pure-tin formulations that predate RoHS. The new
formulations reduce these issues. Here's a good article that refutes the
"gloom and doom" predictions: tinyurl.com/4wxmkz.
Marcus England, by email
Hmmm. Have you ever come across any solder that's pure tin ? It would take a
blowtorch to melt it. Also, there is plenty of research that shows that the
lead in tin-lead solder alloy, mitigates the growth of tin whiskers, whereas
copper doesn't. And anyway, none of the whisker issues alter the fact that
the bloody stuff just doesn't make reliable joints on many component forms,
as anyone involved at the sharp end, would attest to ...
The article that Mr England cites, does not instil a great deal more
confidence in me. Whilst it may be true that *some* cellular phones have
been manufactured in lead-free since 2001, this 'fact' tells us nothing
about the long-term reliability of them, as most are owned primarily as a
fashion statement - even amongst 'mature' businessmen - and only
secondarily as a communications device. This, as well as the fact that the
battery only lasts a short while, dictates that it is replaced on a yearly
basis, which is encouraged by the cellular operators, when they give the
latest all singing and dancing models away, as an incentive to stick with
their network.
Further, this is just one single low power device, As all of us involved in
electronic service work know, there are many other consumer devices such as
TV sets, DVD players, HiFi, microwave ovens etc which, unlike cellphones,
contain large power components and connectors, which do not enjoy good long
term - or often even short term - reliability, when jointed using lead-free
solders. This in no way supports the statement in the article that :-
"This field data indicates the reliability of lead-free assemblies is equal
to, or better than, tin-lead soldered assemblies".
You simply can't make statements like that based on a single product group,
and claim them to have blanket validity.
The further statement ....
"While laboratory studies suggest lead-free solder does not perform as well
in high-stress applications, such as might occur in a ‘drop test', many
applications with these types of concerns (i.e. military) are currently
exempted from RoHS. Meanwhile, alloy developmental work to address lead-free
shortcomings is already underway."
..... contains three areas of concern in that (1) lead-free solder does not
perform *as well* ... (2) some applications e.g. military have concerns
about this, and (3) that it is accepted that the technology has shortcomings
that need to be addressed.
Further, I also have a problem with the first paragraph in the article :-
"Most people incorrectly think the primary intent of RoHS is to protect the
environment. In truth, the fundamental purpose of RoHS is to make recycling
EEE easier and safer."
Protection of the environment was the ticket on which RoHS in general - and
this substitute lead-free technology in particular - was originally sold to
an unsuspecting world. It seems to me that those who make up this
eco-legislation (as they go along, I suspect) are now discovering the error
of their original concept as to why the mature and proven lead solder
technology needed replacing, and are now seeking to bury that error in a
different concept altogether. I can't remember ever before seeing any
reference anywhere to RoHS being primarily to improve the ease and safety of
WEEE recycling, rather than as an environmental issue.
So, far from this article "refuting the gloom and doom", I think it serves
only to further highlight the well known shortcomings of lead-free solder
technology, and unfortunately for Mr England's case, I don't believe that
his letter holds a candle to the two from the other side of the coin, which
preceded it.
Arfa
