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Von: jsmith / unix ([log in to unmask])
An: [log in to unmask]
Betreff: [LF] Component Durability
Datum: Montag, 4. Dezember 2000 22:03
It is surely not the question, if component makers are able ore unable
to produce robust components (I´m sure they do their best), it´s the
simple physical limit: for all kinds of plastic capacitors the melting
point of the foil is not changeable, so this technology and industry
will be killed by the leadfree enthusiasts. Similar for the electrolytic
capacitors, the boiling temperature of the electolyte is not manipulable
as one wants. You mentioned the ceramics, it is also wellknown, that all
kind of ceramics are thermoshock sensitive, the higher the solder tempe-
rature, the higher the shock. Also the mismatch of the different expansion
coefficients, while the soldered component cools down on the board from
the higher soldering level leads to cracks. One question at the end,
if You buy a new car, do You prefer a "green" antiblocking brakes system,
or the "old" one?
With kind regards,
Hans Juergen Bauer
Industrial Engineering
Passive Components
Qualification
ALCATEL Stuttgart
Pondering some recent postings on this forum, I began questioning some
of the assertions that eliminating lead is feasible. Specifically, I
wondered about the current inability (or, at least, lack of rating) of
many parts to survive temperatures in the 260°C range (many larger
ceramic capacitors, for example, are not warranted to survive immersion
in solder above approximately 230°C for even a few seconds). If lead is
removed from solder, the components will be required to survive at 260°C
or higher for quite a large number of seconds.
If the components can be made to tolerate higher temperatures without
degradation when new solder(s) with higher melting temperature(s) are
introduced, why haven't component manufacturers already made their
devices more robust?
Jim Smith
Managing Director
Cambridge Management Sciences, Inc.
4285 45th St. S.
St. Petersburg, FL 33711-4431
Tel: (727)866-6502 ext. 21
Fax: (727)867-7890
eMail: [log in to unmask]
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