David
This translates to nothing because:
- We don't know the temperature swing in your application.
- 5 min. dwell time at -55 degC is as much as nothing, thus no strain is induced.
- 10 degC / min is very fast below 20 degC and you are very likely to activate degradation mechanisms that do not occur in reality.
Running a test
- 0 / 120 degC
- 4 degC / min up to 20 degC
- 10 degC / min above 20 degC
- dwell time of 5 min at 120 degC
- dwell time 30 min at 0 degC
would give in my opinion the possibility for a rough estimate of the lifetime in a realtime environment by
Nfr = Nft ( dTt / dTr )exp1.7
Nfr = Number of cycles to failure reality
Nft = Number of cycles to failure test
dTr = Temperature swing reality
dTt = Temperature swing test
Best regards
Guenter
Guenter Grossmann
Swiss Federal Institute for Materials Testing and Research EMPA
Centre for Reliability
8600 Duebendorf
Switzerland
Phone: xx41 1 823 4279
Fax : xx41 1823 4054
mail: [log in to unmask]
---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------