Your Reliability Engineering Professional Development Site
I would ask why would you do that, yet I probably know.
You are looking for reliability information about a component or system. You want to know something about the expected failure rate or durability. Will it last long enough to meet your design and customer requirements?
Or, you have heard of MTBF and want to understand the acronym and metric. Maybe how to calculate the value from test results or field data. [Read more…]
Every now and then we receive a customer request concerning reliability. If asked most customers would prefer no failures, low-cost of maintenance or ownership, and trouble-free long-term performance. And, many also realize that failures do occur. Thus a series of discussions occur to find the economically viable solution for both parties. Part of this discussion may include a poorly worded reliability requirement.
How you respond can help to improve the discussion and accelerate the finding of the right solution.
Just because the vendor provide the data convenient for an MTBF calculations should you settle?
No.
You have some questions to ask and some better information to gather. You may have a decision to make and using the best possible data helps you and your team make the right decision more often.
Reliability engineers usually work in support of an organization. We support a development team as they design a new product. We support a factory as they operate equipment to produce products. We support using our specialized knowledge to create and maintain reliable products or assets.
The teams we work with consider cost, time, function, technology, environmental impact and many other factors as they find a viable solution. Reliability is just one of the many considerations.
Let’s say you join a project as a reliability professional (or an engineer or manager of any type) and you discover that the team as a reliability goal stated as 5,000 hours MTBF.
What are you going to do with that information?
This past couple of weeks have been great.
First, I heard about a webinar by Craig Hillman of DFR Solutions titled “MTBF. Is There a Better Way?” and you can find the recorded event on the DFR Solutions site.
“The language we use matters.” Wayne Nelson
When we talk about our products or equipment, we may refer to the expected durability of the system.
Our customers and investors also want to know how long will it last.
When using the term, MTBF, many believe they are talking about the reliability of a device or system. A high MTBF numbers means it is a reliable item.
What we really want is the device to work over some duration without failure (or with few failures). It should perform a function as expected in the desired environment.
MTBF is taught in many textbooks and introductory reliability courses. There may be some mention of Weibull and other distributions. You may even learn about the four functions: – reliability – probability density function (PDF) – cumulative density function (CDF) – hazard function
One of the major risks for product reliability is bad components. Either not suited for the system or adverse variation over time from the supplier.
Reading data sheets and hoping for the best is often all we have time to accomplish. For high risk (new technology, new supplier, new… something) many organizations will examine the reliability claims to some extent. Some may even conduct reliability testing in-house to validate vendor claims.
A table of numbers is not information, it is data. It is information that we need to make decisions, to notice differences and to detect patterns. It is a plot of the data that is often all that we need to interpret the data.
What do customers want when they say they want reliability?
Maybe it is that the product will work when they need it to work.
Like your car starts in the dark parking garage after a long snowy day so you can head for home. The goal is getting home.
Last year I offered a coveted NoMTBF coffee mug to the most traffic generating guest post.
This year, my challenge is for the best success story around your efforts to reduce or eliminate MTBF from use in your organization.
The basic idea is we all have a role to play to clean up the reliability profession. Using clear language is a start. Avoiding the mis-understanding around MTBF is a great start. If we all do something, great or small, toward the goal of eradicating MTBF we all benefit. [Read more…]
One of my regular questions with clients and students is, “How do you talk about reliability, which metrics, measures, or statements do you regularly use?”
Some have learned to avoid mentioning MTBF around me. Which is fine, and if they are really using MTBF to discuss reliability then they probably know my position.