TECHNET Archives

November 2000

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Guenter Grossmann <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Wed, 22 Nov 2000 16:08:51 +0100
Content-Type:
text/plain
Parts/Attachments:
text/plain (48 lines)
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
---------------------------------------------------------------------------------

ATOM RSS1 RSS2