Thanks, Werner, und Günther and David,
It seems it was too early for such a question.
Is anybody aware of a study in any lab or consortium to find the necessary
data and achieve the acceleration models ?
Merci,
Pascal Guihéneuf
Nortel Wireless
UMTS NPI/LCM
GSM/UMTS Environmentally-Friendly Core Team Leader
ESN 574-5382 or 33.1.69.55.53.82 (phone)
ESN 754-2704 or 33.6.64.04.27.04 (mobile)
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]]
Sent: lundi 10 janvier 2005 17:22
To: [log in to unmask]
Subject: Re: [LF] Lead-Free Acceleration Factor
Hi Pascal,
Acceleration factors for LF-soldrs do not as yet exist--the necessary data
simply have not been generated. Your cycle time of 40 minutes is much too
short for any significant creep to have taken place and thus you do not get
the necessary creep-fatigue. For IPC-9701A, we are discussing 30 minute hold
times at each temperature extreme, fully realizing that even this is
inadequate relative to the 10 minte hold times prescribed for SnPb-solders.
This is because the creep rates for LF-solders are almost a factor of 100
slower than for SnPb
solders. While this is a good thing for the reliability of product that
experiences short period cycles, it makes accelerated testing for prodcut
that sees something like one cycle/day essentially impossible without the
existance of acceleration models.
Regards,
Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting 7 Jasmine
Run Ormond Beach, FL 32174 USA
Phone: 386-437-8747, Fax: 386-437-8737, Cell: 386-316-5904
E-mail: [log in to unmask], Website: www.engelmaier.com
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