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MTBF interpretation

MTBF interpretation

MTBF interpretation

(OP)
Hello,
If MTBF value is 120 yrs, and 7 units failed out 1200 units, how is this translated in to ppm or % wise?
Regards

RE: MTBF interpretation

MTBF is not exactly the right value for predicting the number of failures of a certain amount of units.  You'll need to figure the actual probable failure rate to figure failures of parts per million.

MTBF will allow you to predict the probability of a part working based on a certain time.  R(T)=exp(-T/MTBF)  T is the time you're interested in and R(T) is the probability the part will work over that course of time.

Hope that helps answer part of your question.

- Kyle

Kyle Chandler
www.chiefengineering.net

"To the Pessimist, the glass is half-empty.  To the Optimist, the glass is half-full.  To the Engineer, the glass is twice as large as it needs to be!"
 

RE: MTBF interpretation

What is your physics of failure, is exponential the correct distribution?  I agree with the Kyle, you will need to calculate reliability at a given time to get ppm.



 

RE: MTBF interpretation

You need to also determine whether the MTBF is predicted for the same environmental conditions that the systems that failed were operating in.

A higher ambient temperature could easily double or quadruple the failure rate.

TTFN

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