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Forum: Reliability & Maintainability Questions and Answers

Topic: Reliability & Maintainability Questions and Answers

Topic Posted by: Reliability & Maintainability Forum ( )
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998

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Posted by: Tom Donnelly ( )
Date posted: Sun Jan 3 1:59:31 US/Eastern 1999
Subject: Screening solder workmanship
I am currently working with space related hardware. The issues I am having are with solder joint reliability and possible sources for specific failure rate information as it relates to the thermal stress testing of PWB's. What is the difference in solder joint failure rates when the electronic equipment is exposed to -45F versus -30F? and what failure mechanism's did I miss by only exposing the equipment to -30F. I have the same question for taking the equipment to +60F instead of +85F. What is the differnce in failure rates for the solder connections and what failure mechanism's did I miss. From my many years in Reliability I believe that the difference is insignificant, but my customer's would like me to quantify it....I appreciate any thoughts you could contribute to solving this problem...... T.Donnelly


Subject: Thermal stress testing of PWBs
Reply Posted by: Larry Mosher ( )
Organization: Abex NWL Division of Parker
Date Posted: Tue Jan 5 14:56:16 US/Eastern 1999
Several years ago, I evaluated a software package called "PRAC" from International Analytics Co., P.O. Box 2051, Huntsville AL 35804-2051. Phone 205/539-8118. This package modeled both thermal stresses and vibration stresses and predicted solder joint life. It struck me as very easy to use and relatively cheap ($1500 in 95).

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