cycle testing one sample

Posted on 2012-08-20
Last Modified: 2012-08-21
Good Afternoon,

We are going through legacy test procedures to determine failure probabilities for evaluating the efectiveness of tests, whether more samples and/or cylces/specimens should be performed to assure a low enough failure probability at a high level of confidence.

One of these legacy tests is performed on one sample of a mechanism 30 times.  If the mechanism does not operate one time in those 30 cycles, the entire population of the mechanism fails.

What failure probability and confidence level is associated with this test, and what should it be, if not it's current probability and level?

I appreciate any guidance you can provide.

Thank you

Question by:aasikolo
    1 Comment
    LVL 26

    Accepted Solution

    What is the reliability required or claimed for this product?
    What is the expected lifetime?
    What is the reliability history?
    How many samples does this one tested item represent?  What is the batch size?

    What is the cost of the product, the cost of the test?
    What is the cost associated with a single failure in the field?  

    What is the cost or discarding an entire production run?
    Has this ever happened?  Has any unit ever failed during this test?

    Have any units ever failed in the field?  If so, what were the failure modes?
    Does your test address these modes?

    What is the a priori estimate of selecting a "good" mechanism from the population?
    What are a priori estimates for a "good" and "bad" mechanisms passing the cycle test?
    Why not test 15 mechanisms for one cycle each?
    Historically, how many cycles does it take to discover a "bad" mechanism?

    It is difficult to provide much guidance with so little information, but the test as you have described it doesn't inspire any confidence at all.

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