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What is wrong with the existing reliability prediction methods?
Author(s) -
Wong Kam L.
Publication year - 1990
Publication title -
quality and reliability engineering international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 62
eISSN - 1099-1638
pISSN - 0748-8017
DOI - 10.1002/qre.4680060407
Subject(s) - reliability (semiconductor) , reliability engineering , computer science , statistics , power (physics) , engineering , mathematics , physics , quantum mechanics
Inaccurate reliability predictions could lead to disasters such as in the case of the U.S. Space Shuttle failure. The question is: ‘what is wrong with the existing reliability prediction methods?’ This paper examines the methods for predicting reliability of electronics. Based on information in the literature the measured vs predicted reliability could be as far apart as five to twenty times. Reliability calculated using the five most commonly used handbooks showed that there could be a 100 times variation. The root cause for the prediction inaccuracy is that many of the first‐order effect factors are not explicitly included in the prediction methods. These factors include thermal cycling, temperature change rate, mechanical shock, vibration, power on/off, supplier quality difference, reliability improvement with respect to calendar years and ageing. As indicated in the data provided in this paper any one of these factors neglected could cause a variation in the predicted reliability by several times. The reliability vs ageing‐hour curve showed that there was a 10 times change in reliability from 1000 ageing‐hours to 10,000 ageing‐hours. Therefore, in order to increase the accuracy of reliability prediction the factors must be incorporated into the prediction methods.