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A listing in reverse chronological order of articles by:
A common error in FMEA procedure is to make entries in the Controls column that the FMEA team believes need to be done, but are not currently planned or in place. Why is this error so prevalent? Maybe the question should be why do we limit entries into the prevention or detection control column to actions or methods that are currently planned or in place?
“Never mind your mistakes. One day they will become your most prized possessions.”
Abhijit Naskar
Is it a good idea to do one generic FMEA for wiring harnesses, and use it as a reference for other FMEAs for similar applications? What about interfaces? These questions are discussed and answered in this FMEA Q and A article.
“We live in the world our questions create.”
David Cooperrider
Telematics data presents the opportunity to characterize the vehicle lifetime usage. This information is used to validate development and testing targets. Because there can be bad or missing data, it needs to be reviewed prior to analysis to have confidence in the analysis. [Read more…]
The DC-10 case study continues by asking for causes to the door latch-pin failure. The advanced problem poses a realistic and especially challenging circumstance that FMEA teams can experience.
“Judge a man by his questions, not his answers.” Voltaire
Does a cause description need to be a design or manufacturing deficiency? Why? This is one of the more important questions to consider if you want to achieve quality FMEAs.
“The effort to get at the truth has to precede all other efforts.”
Albert Einstein
In this Q and A article, a reader asks a challenging question about the linkage between FMEA boundary diagrams and Design FMEAs. There are many linkages between different elements of FMEAs, and this question/answer highlights one of the key linkages.
“In all affairs, it’s a healthy thing to hang a question mark on the thing you have long taken for granted.”
Bertrand Russell
In my prior article, “A Primer on Probability Distributions”, the usage of different types of histograms to display data was discussed. The histogram would acquire a bell shape if the data were normally distributed. The main limitation of the histogram approach is that the shape of the histogram can change radically with the selection of the bins used. Instead, a probability plot could be used.
This article discussed probability plots. They are extremely useful for the analysis of big and small data sets.
Can you identify the effect of the door latch-pin failure in this case study? The loss of the aft cargo door on the American Airlines DC-10 aircraft will be the focus of this Problems and Solutions article. This real-life case study is being used to practice identifying FMEA elements.
Why do you think FMEA procedure requires effects to be taken to the system or end user? Why not describe the consequence only at the local level. If a bolt in a complex system fails, the parts that the bolt was clamping together may come apart. Isn’t that enough?
“Wisdom consists of the anticipation of consequences.”
Norman Cousins
Frequently, data collection is the most time consuming and expensive part of a project. Consequently, people work with small sample data. There is too little data to plot a histogram, so the analysis assumes the underlying population is normally distributed.
A frequent error is to assume the sample average and standard deviation are the population normal mean and standard deviation. When small sample sizes are being analyzed, these assumptions lead to estimation errors.
Methods to make better estimates are discussed in this article. [Read more…]
In this Q and A article, a reader asks an interesting question about whether or not to update a System FMEA, when making subsequent changes to lower-level items. This is an excellent question, and shows the reader has good insight into the application of FMEA.
“Judge a man by his questions, not his answers.”
Voltaire
Whether you are new to FMEA or more experienced, these problems will challenge your skills. The intermediate/advanced problem uses an actual airline disaster to challenge readers with an FMEA problem, and practice identifying the elements of an FMEA.
The most common types of engineering data are measurements. There can be a few, thousands, or millions of data points to analyze. Without analytic tools, one can get lost in the data.
This article presents
To reduce schedules, prototype cycles are often randomly slashed. Eventually the time and resources are needed and create cost and schedule over runs. We need to recognize that prototypes exist to help us learn about our product. If we use a risk based test strategy approach, we can test at lower levels to gain the required understanding. Then, we can confirm our learning with the higher level, system prototypes.
Just 4 minutes and 19 second long. To me, a prototype does include bench testing at lower levels as long as it includes the relevant functionality to represent the area for learning. [Read more…]
Do you know why we ask for the “mode” of failure when performing FMEAs? This article will provide theory and practical examples of defining failure modes, and highlight an application tip that can improve your FMEA effectiveness.
“I haven’t failed, I’ve just found ten thousand ways that don’t work”
Thomas Edison
