Your Reliability Engineering Professional Development Site
This is my second video on Sample Size in Reliability Testing! In this video, we will explain the Weibayes Approach to estimate sample size and estimating test length when sample size and shape parameter is known.
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Insert these pages into your copy of MIL-HDBK-217. The boldface text is changed to MIL-HDBK-217E [1], section 5.2, on parts count reliability prediction. The changes explain how to use “Paretos,” proportions of parts failing in the field, to compute a reality factor that makes predicted Paretos match field Paretos. You can use field Paretos to calibrate predictions for new equipment. You probably have field Paretos on related parts used in your other equipment, which is now in the field. Remember, the field determines reliability.
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I have a service that regularly monitors my home for termites. Using RCM, let’s determine if this Condition Based Maintenance task is both technically appropriate and worth doing.
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The bottom line is reliability engineers must balance honesty and transparency with the pressure to meet business and customer expectations. The second E in the FINESSE fishbone diagram stands for Ethics. Three types of ethics are virtue, consequential, and duty-based. The most important aspect is understanding your ethical framework as you make decisions and communicate to others as a trusted advisor. These three tips will help you improve.
Thanks to a reader that noticed my question on why MTBF came into existence, we have a new (new to me at least) rationale for using MTBF. Basically, MTBF provides clarity on the magnitude of a number, because a number in scientific notation is potentially confusing.
What is doubly concerning is the use of MTTF failure rate values in ISO standards dealing with system safety.
Let’s explore the brief email exchange and my thoughts. [Read more…]
Why is confidence level so important in engineering test data analysis?
From the name itself it gives us a very good hint; Confidence level is giving the confidence in data analysis. In the next graph, you can find 10 samples and fitted Weibull 2p distribution with 95% of Confidence level:
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Safety Projects International Inc. discusses how to handle different types of crises that may arise at your facility. If 2020 has shown us anything, it’s that we need to adapt to outside elements that may affect your team processes and procedures. Let’s get started on a crisis management plan.
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A definition: Maintenance describes the management, control, execution and quality of those activities which will reasonably ensure that design levels of availability and performance of assets are achieved in order to meet business objectives. [Read more…]
Dear friends, I am happy to release this video about determining sample size in reliability and functional testing! The video discusses determining sample size with Success Run Theorem (or Success Testing) will zero failures as well as given number of failures. I have illustrated use of basic formula and calculation as well as use of various templates to determine sample size. Hope you find this important and interesting!
This is part-1 of my videos on sample size! We recommend viewers to watch our video on Binomial Distribution before watching this video, in case they have not seen it before
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Today we are going to look at Design Rates. Often times our equipment are not running at their designed rate. Most of which are operational issues. For example, we tend to slow down a line, to present less problems, but it lowers the target rate. How do we identify an actual opportunity?
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Hard work alone doesn’t guarantee success in business. Even after you’ve invested your inspiration, money, emotions, creativity, and prayers, the reality is that we live in a highly competitive world. You can’t afford to simply tread water. So, let’s assume you’ve either made a strong start in your field or joined a profitable company. What ensures that your future will be better than today? The answer lies in leadership and the team deciding to continually evolve, change, and improve.
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There might not ever be a better demonstration of the saying that …
… a fish rots from it’s head.
Boeing is responsible for the half-baked Maneuvering Characteristics Augmentation System (MCAS) that was forced into its new 737 Max aircraft. This involved a decidedly awful attempt to convince the Federal Aviation Administration (FAA) that there was no need to subject said aircraft through all the checks and balances that you need to go through if it is in fact a brand-new and different type of plane. Which it was. This resulted in the deaths of 346 passengers and crew (along with plenty of claims that it was pilot error). And just to be clear, Boeing has since admitted that it’s employees defrauded the FAA during the original certification process – an admission it was not required to make if it was able to complete a three-year period of increased monitoring and reporting. Which it could not.
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In his book Reliability Centered Maintenance1, John Moubray highlights 6 patterns of failure. However, one needs to be careful about how those patterns are interpreted and used. Or misused. These 6 failure patterns are as follows:
Guest post by Msc Teofilo Cortizo
The term MTBF (Mean Time Between Failures) within maintenance management, it is the most important KPI after Physical Availability. Unlike MTTF (Mean Time To Failure), which relates directly to available equipment time, MTBF also adds up the time spent inside a repair. That is, it starts its count from a certain failure and only stops its counter when this fault was remedied, started and repeated itself again. According to ISO 12849: 2013, this indicator can only be used for repairable equipment, and MTTF is the equivalent of non-repairable equipment. [Read more…]
Exploring the differences between HALT and ALT, or Highly Accelerated Life Test and Accelerated Life Test. Plus when to use which when.
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