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In the past two months, I’ve received a few questions concerning why I recommend avoiding using MTBF or similar metrics. I’m also moving the articles I and others wrote on the topic from NoMTBF.com to Accendo Reliability. So, the topic of MTBF has been on my mind.
This morning’s email included a question on why I was so against using MTBF. This event is my answer. [Read more…]
In the past two months, I’ve received a few questions concerning why I recommend avoiding using MTBF or similar metrics. I’m also moving the articles I and others wrote on the topic from NoMTBF.com to Accendo Reliability. So, the topic of MTBF has been on my mind.
This morning’s email included a question on why I was so against using MTBF. This event is my answer.
[Read more…]
First thing … the MTBF is not a reliability metric (other webinars explain why!) But there are many times when (for reasons good and bad) we need to test something to see how often it fails. This can help us determine how many spare parts we need, how many maintainers and technicians we need to employ, and many other really useful (typically logistic) considerations. We sometimes also need to be able to work out if a product meets an MTBF requirement. But when we do … we need to take into all sorts of statistical considerations like producer’s risk, consumer’s risk, and discrimination ratio. Shouldn’t the requirement be the requirement? If you want to learn more about MTBF testing and how it might (or might not) work … then join us for this webinar.
[Read more…]First thing … the MTBF is not a reliability metric (other webinars explain why!) But there are many times when (for reasons good and bad) we need to test something to see how often it fails. This can help us determine how many spare parts we need, how many maintainers and technicians we need to employ, and many other really useful (typically logistic) considerations. We sometimes also need to be able to work out if a product meets an MTBF requirement. But when we do … we need to take into all sorts of statistical considerations like producer’s risk, consumer’s risk, and discrimination ratio. Shouldn’t the requirement be the requirement? If you want to learn more about MTBF testing and how it might (or might not) work … then join us for this webinar.
Chris and Fred discuss the pointlessness of the MTBF. This comes from a listener who reached out to complain about how lots of industries enforce the MTBF … but why?
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It’s my pleasure to welcome Fred Schenkelberg back to the podcast. He is a reliability engineer and management consultant.
In this episode we covered:
There’s a big difference between MTBF and Useful Life. The two values are often misunderstood and misapplied when assigning Preventive Maintenance task intervals. In this video, I’ll explain which one is used to assign intervals for Scheduled Replacement and Scheduled Restoration tasks. We’ll also discuss Operating Context and how that can affect Manufacturer Recommended Maintenance. This is an “edutainment” video. If you’d like to skip the fun stuff (although I don’t know why you’d want to ☺️), I’ve time stamped the Reliability Moments below. Enjoy!
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Chris and Fred discuss … MTBFs! Fred’s favorite! We (should) know that Mean Time Between Failure (MTBF) is not reliability. So what do we do if we somehow need to get reliability from nothing but the MTBF.
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Chris and Fred discuss the MTBF … and if and when it can be used … sometimes in reliability engineering. We know that the MTBF is one of the most chronically overused (and misused) so-called ‘reliability’ metrics. But is there scope for it to be used … sometimes?
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Philip and Fred discussing a listener question about how to verify vendor claims about reliability.
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Kirk and Fred discussing how testing a small sample size of a new product results on a larger margin of error for the larger population.
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While the NoMTBF movement is progressing, we still find those who want to use MTBF (or MTTF). As you know, MTxx-type metrics are means. They contain little information and are generally misunderstood and misused. So, what should a well-educated practitioner do? [Read more…]
While the NoMTBF movement is progressing, we still find those who want to use MTBF (or MTTF). As you know, MTxx-type metrics are means. They contain little information and are generally misunderstood and misused. So, what should a well-educated practitioner do?
[Read more…]
“What’s the MTBF of a Human?” That’s a bit of a strange question? I ask this question in my Reliability 101 course. Why ask such a weird question? I’ll tell you why. Because MTBF is the worst, most confusing, crappy metric used in the reliability discipline. Ok maybe that is a smidge harsh, it does have good intentions. But the amount of damage that has been done by the misunderstanding it has caused is horrendous. MTBF stands for “Mean Time Between Failure.” It is the inverse of failure rate. An MTBF of 100,000 hrs/failure is a failure rate of 1/100,000 fails/hr = .00001 fails/hr. Those are numbers, what does that look like in operation? [Read more…]
