Werner
Very interesting article. However, it is not all about lead-free solder.
I am quite alarmed at the notion of Proofcap. The test figures given are
for the Middle East, where climatic conditions are quite benign, with
very low daytime humidities. As an inhabitant of somewhere very close to
the ME, our summer RHs descend to 24% RH and, yes, if the RH in the
enclosure is higher, some of the humidity will be pumped back out. But
what about Kuching, Kuantan and other places where the daytime RH is
90-95% at 32°C, rising to 99-100% at 26°C at night?
The last time we lectured together in the same session, somewhere near
Lugano, if I remember correctly, I talked about the Walk-home syndrome
(for those not aware of this disease, it is the immediately irreparable
fault of a vital part of a car, causing the occupants to have to walk
home). A few years ago, before electronics found their way into vital
parts, there were a number of causes of the WHS, especially ignition
systems, blocked fuel lines, brakes and mechanical failures of the
suspension, engines etc. With progress, most of these problems have
considerably diminished, but not so for electronics. I demonstrated
statistics that showed that one of the major causes for the WHS has
become vital electronics. It was interesting that these also showed that
figures published by the European motoring organisations correlated to
whether the vital electronics were cleaned or not.
However, a cold MTBF is not sufficient. If you are travelling fast along
a motorway in dense traffic and the electronics of your car decide to
render their soul, you can be dead meat. If you are on slushy, salted
snow and your ABS fail, you can end up into a 42 tonne truck coming in
the opposite direction. Ideally, the MTBF must be infinite, and this is
what we should strive for. 100 ppm failure in the first 20,000 km of a
car's life is simply not acceptable in the long term, even assuming you
live to walk home. It means that 1 new car in 1,000 may be the potential
cause of a serious accident. What were the figures for the tyre failures
on the total number of SUVs of that model sold?
Whereas lead-free solder will probably contribute to a rise in fatal
accidents, if used for vital electronics, let us also take a more
holistic view of car electronics reliability.
Brian
Werner Engelmaier wrote:
> Hi Joyce & All,
>
>>Oh, well, guys, I have to take trips very often, please keep airplanes
>>(=me...very selfish) safe... (really concerned):
>>http://www.imaps.org/adv_micro/2002may_jun/2.html
>>jk (I don't think technet is ready for it yet...so, I just send to you all)
>
>
> Joyce, I think you underestimate TechNetters.
> The article accessible at http://www.imaps.org/adv_micro/2002may_jun/2.html
> should be required reading for the whole electronic industry. It highlights
> how bad that the push towards lead-free solder is.
> The push to lead-free solder is obviously a very grave insidious danger to
> life and property.
> Since Japan and perhaps soon Europe mandate lead-free solder, the US can only
> fight this by not permitting import of electronic products containing nothing
> but lead-free solder.
>
> Werner Engelmaier
>
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