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Lead free solder - exposed in a UK national newspaper

Discussion in 'Electronic Repair' started by N_Cook, Apr 3, 2008.

  1. krw

    krw Guest

    Is THAT why you wear a different pair of you mommy's stockings every
    day?
    ....and you live with stupid!
    You couldn't stand the truth, Dimbulb.
     
  2. You're an idiot. You're a goddamned idiot.
    You're a goddamned idiot.
    You wouldn't know... You do not know what the truth is.
     
  3. Rich Grise

    Rich Grise Guest

    What is it you don't like about hookers? Too much like true Free Market
    Capitalism? ;-)

    Thanks,
    Rich
     
  4. krw

    krw Guest

    From you, that's a supreme compliment.
    Look in the mirror, Dimbulb.
    IKYABWAI
     
  5. JosephKK

    JosephKK Guest

    For street lighting, warehouse lighting, and industrial lighting there
    is a competing technology: Induction lighting. Typical lamp/bulb life
    50,000 to 75,000 hours. Twice the life and better luminous efficacy
    at a 50% surcharge compared to HID lighting. It is starting to get a
    lot of notice. Oh, and better electrical efficiency, takes about half
    the power for the same amount of light.
     
  6. Arfa Daily

    Arfa Daily Guest

    I don't know how much take-up of this technology there has been in the UK.
    It does beg the question of how much trouble it could cause, if a single
    streetlamp or warehouse luminaire went 'rogue'. Already, I see fellow hams
    bleating all the time about HF bands interference problems from rogue CFLs,
    and SMPS's and PLT and so on. Imagine the potential for interference if a
    high power streetlight ballast, feeding an induction lamp 50ft up a pole,
    started radiating on 13 odd megs. Or a factory one 50ft up in the ceiling
    .... :)

    Arfa
     
  7. N_Cook

    N_Cook Guest

    more printed followup
    http://www.guardian.co.uk/technology/2008/apr/17/1
    # The Guardian,
    # Thursday April 17 2008
    Tin woes solder on

    Congratulations on the very interesting article on tin whiskers (Within a
    whisker of failure, April 3). You may be interested to hear of another
    phenomenon associated with lead-free solders in electronics, known as tin
    pest. Research was carried out into the allotropy of tin 80 years ago. Tin
    pest was found to occur by a process of nucleation and growth of "grey" tin
    (a form found below 13C), and was very slow - often requiring years to
    complete. Since the transition from "white" to "grey" tin involved a 27%
    increase in volume, its formation was restricted to the surface. Recently,
    tin pest has been reported in bulk samples of lead-free solder alloys
    following a few years' exposure at -18C, the usual freezer temperature.

    To date it has not been observed on actual joints. But lead-free
    interconnections have been in service for a relatively short time. Although
    we do not know whether it is necessary to shut the stable door, we should
    make more effort to understand and control tin pest formation. Only time
    will tell whether it represents a real problem in electronics.
    Professor Bill Plumbridge
    Faculty of Technology
    The Open University
     
  8. JosephKK

    JosephKK Guest

    In the US they have to meet FCC radiated and conducted emission
    standards. Thus the CFLs going rouge probably only statistically meet
    those standards, such is part of the nature of regulation.
     
  9. Arfa Daily

    Arfa Daily Guest

    They have to meet strict emission regulations here too, which I'm sure for
    the most part, when in full working order, they do. The problems arise when
    the crappy little filter caps in the front end of the switching driver for
    the tubes, go open circuit or high ESR, due no doubt to the unventillated
    enclosure in the bottom of the lamp, that the electronics sit in, running
    very hot. Once that cap has failed, the inverter radiates like a bastard,
    swamping the airways with broadband hash. It's bad enough when one goes
    rogue like this, 6 foot off the deck in someone's driveway light outside
    their house. Think what it would be like if one went bad 50 foot up in the
    air ...

    Arfa
     
  10. Arfa Daily

    Arfa Daily Guest

    'Plumb' -ridge. What an appropriate name for someone versed in lead matters
    ! Seriously though, I'm really glad that the scientific establishment is
    finally making some anti lead-free noise, and backing up with genuine
    science, what we lowly service engineers have been trying to tell the world,
    since the first day that this hateful material was foisted on us by self
    serving bureaucrats with a politically 'green' agenda ...

    Arfa
     
  11. JosephKK

    JosephKK Guest

    Please explain under what situations would a cfl be mounted 50 feet
    above ground.
     
  12. Arfa Daily

    Arfa Daily Guest

    Block of flats ? Might be 100 feet up in the air or more in that case. When
    the EU morons responsible for all this eco-bollocks legislation finally ban
    incandescents in the UK, as they have stated that they will in short order,
    then tower blocks will be full of CFLs, as there will be no alternative, yes
    ?

    Originally, when we got onto lighting being 50 foot up in the air, we were
    talking about induction lighting in street lamps and factory ceiling lights.
    The point was that these devices use high frequency generators to couple the
    energy into the lamps, and these generators follow similar design principles
    to the tube driver inverters in CFLs. Thus, if low power CFL inverters go
    bad, and create the RF havoc that they sometimes do at just a few feet off
    the ground, then imagine how bad the situation would be if the high power HF
    generator for an induction lamp, 50 foot up a pole, when similarly bad. With
    my thinking now ...?

    Arfa
     
  13. JosephKK

    JosephKK Guest

    Most of those will be converted to HID lighting or induction lighting
    instead of cfl over the longevity characteristics.
     
  14. The fact is that the amalgam used by the dentists uses the Mercury to
    bind the other metals together covalently.

    As the dentist presses the silver amalgam into the filling cavity, the
    mercury squeezes out and is recaptured by the dentist.. This means that
    your fillings are like 95% Silver, and a few percent of other metals, and
    less than one percent of metallic form Mercury.

    NOT A HEALTH HAZARD.
     
  15. Arfa Daily

    Arfa Daily Guest

    ?????????

    Arfa
     
  16. Arfa Daily

    Arfa Daily Guest

    My feeling too ...

    Arfa
     
  17. JosephKK

    JosephKK Guest

    Most street lighting is HPS currently with a normal ballast, there are
    some MH lamps with normal ballasts. LED street lighting is being
    experimented with. Caltrans in using induction lighting on signs and
    may branch out into other uses. Since induction lighting is targeted
    at hard to maintain locations in commercial and industrial settings
    there are design differences from household CFL where cheap is the
    dominant factor. Where we will see CFL is on smaller apartment
    buildings with penny-pinching owners / managers.
     
  18. Arfa Daily

    Arfa Daily Guest

    Ah, OK. I see what you're saying now. I guess that LED lighting is going to
    become the standard when they can get them high enough powered. This can't
    be too far away, as I see that car manufacturers are starting to experiment
    with LED headlights. Already, Audi seem to have LED front running lights,
    set into the headlight units, and some of the front lamps used on bicycles
    now output enough light to see the road ahead. A local night club had
    coloured floodlights on the front of the building, which were LED based, and
    I was amazed at just how good a job they did.

    Elektor magazine carried out an interesting project last month. They took a
    DLP video projector with a standard expensive HID lamp and colour wheel, and
    canibalised it to fit an array of red, green and blue Luxeon LEDs in its
    place. They then programmed up a cheap microcontroller to emulate the
    rotation of the colour wheel, by switching the colours of the LEDs with 3
    FETs. They also fed a colour sync signal from the micro to the original
    optical sync pickup, so that the LED switching remained synced to the DLP
    chip drive. Colour balance was achieved by tweaking the 'on' times of the
    LED colours, in software.

    The conclusion was that although not as bright as the original HID lamp, the
    projector did produce a perfectly useable picture, which proved what they
    set out to, which was that it was perfectly possible to use LEDs in place of
    a lamp, and that it would be just as good, once they had got the luminous
    output up just a bit more.

    Arfa
     
  19. N_Cook

    N_Cook Guest

    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
     
  20. Arfa Daily

    Arfa Daily Guest

    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
     
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