Forum: Reliability & Maintainability Questions and Answers
Posted by: Uma
Date posted: Tue Aug 20 14:42:14 US/Eastern 2002
Subject: How to handle inductors, oscillators and connectors in PRISM
I have been using MIL-HDBK-217FN2 and Telcordia/Bellcore SR-332 for my reliability analysis. I have part types such as inductors, oscillators, filters, connectors etc in my product. How do I use PRISM to perform reliability analysis? RACRate models are not available for these part types. Why? Will they be available in the near future?
Posted by: Uma
Date posted: Tue Aug 20 14:37:17 US/Eastern 2002
Subject: Year of manufacture (used to calculate piG) in PRISM
Is the year of manufacture (used in calculation of growth rate pi factor piG)the year a part was first manufactured? Or is it the year you bought it?
For eg. if I buy a transistor today, is the year of manufacture 2002, or is it the first year this type of transistor was first manufactured?
Posted by: Steven Pennington (firstname.lastname@example.org )
Date posted: Thu Aug 15 21:02:52 US/Eastern 2002
Subject: Strain Gage Relaiblity
I need reliablity data, and screening methods for screening and providing a relaibity model for bonded foil strain gages.
Also we have some custom parts which have been grandfathered, which are a part of a screening program similar to space level quality but are custom. Can I use piQ for space quality parts? One last question, what if the reports that where done for the last 25 years are wrong (misleading) and my company knows it?
Posted by: sastri
Date posted: Thu Aug 8 12:07:52 US/Eastern 2002
Subject: dormant storage life
I am looking for models and accelerated test methods that would enable me to predict the preformance of electronic and mechanical parts placed in a relatively stable environment. The subsystems have to perform after being dormant for a long time.
Posted by: John K (email@example.com )
Date posted: Thu Aug 1 11:25:44 US/Eastern 2002
Subject: Calculating Reliability Growth
When calculating MTBF: Is there a preferred method for determining how much additional test time is needed relative to the previous MTBF in order to do the next calculation?
Example: Four units are under test (MTBF target = 300 hrs, each unit is repaired and returned to test), your first MTBF (cumulative) calculation indicated a MTBF of 100 hours. In order to do your next update (calculation) is there a recommended number of additional hours needed? More than 100 hours or some multiple of 100 hours? or is less OK? Keeping in mind management wants regular MTBF updates (weekly). How do you handle this? Any references or comments would be greatly appreciated.