David, trying to echo what Brian said, what is the product?  An IC wire bond?  Backplane?  Assembly with surface mount solder joints?  People have asked me about the main challenge for the reliability profession these days.  I think the most difficult one is the development of credible accelerated hardware tests, since that would involve stressing in extreme lab environments for relatively long times along with collection of operational data over even longer times.  (I'm staying away from questions about software quality and reliability.)  Best of luck.  

I've struggled with your question many times.  I believe there is value in environmental stress screening, which may involve thermal cycling as you describe (or a milder version), to eliminate "weak" product.  In fact, I've speculated that "bad" solder joints may be culled out by stress screening, while "good" ones are not degraded any more than they would be in a day or two of normal operation.  Any comments from the knowledgable would be of interest.

Lou Hart
Compunetix
(ASQ Certified Reliability Engineer)

----------
From:   David[SMTP:[log in to unmask]]
Sent:   Wednesday, November 22, 2000 8:48 PM
To:     [log in to unmask]
Subject:        [TN] Temperature Cycle to product life

<<File: ATT00012.htm>>
Hi,

Would like reliability opinions on temperature cycle translating to a product life. For a temp cycle at the following parameters:
-55 to 125 degC
5 mins dwell time on each peak
Maximum ramp at 10degC/min

What would this translate to a product life for 100cycles, 200 cycles and 300 cycles?   

Thanks.

Best regards,
David.

---------------------------------------------------------------------------------
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
---------------------------------------------------------------------------------