Your Reliability Engineering Professional Development Site
A listing in reverse chronological order of articles by:
One of the most difficult challenges of incorporating reliability activities with program planning is estimating the time it will take to demonstrate reliability. Demonstrated product reliability is typically measured as a confidence in a product’s capability to achieve a reliability goal. At product release, the business unit may feel comfortable with their target market and warranty goals with a demonstration of a 90% confidence in the products reliability goal of 99.1%. [Read more…]
Not every request we make is fulfilled. Not every assignment is accomplished. Not every task we assign is completed.
Why is that? Possibly, the lack of a complete request.
It may be the person we made the request to was incapable or decided to ignore us. Or, more likely, it may be our request was not clear.
An unclear request increases the chance the desired outcome will not occur. An unclear request permits misunderstanding and confusion to guide the path toward an unsatisfactory result.
Understanding the essential elements of making a complete request improves the chance the desired outcome will occur.
Let’s examine the 7 elements one at a time. [Read more…]
Here is a common situation that is considered when reliability testing is being planned. Let’s use letters to designate depth in a product component structure. The top level product is level “A” and a component in top sub assembly is “B”. A sub assembly, of a sub assembly, of a sub assembly, is at level “D”. So is it more efficient to test the component at level “E” or at level “B”?
Question: Is it more efficient to test the component at level “E” or at level “B” to demonstrate it’s individual goal? [Read more…]
Reliability engineers have traditionally been asked to answer a common question during development of a new device or system, and that is “How long will it last?”.
It is the eternal question in equipment reliability development, and it really comes down to “that depends on many factors”. One question that needs to be asked is how long do you need it to, or should it last? [Read more…]
Autonomous Vehicles (AVs) are still futuristic – but there are plenty of people are thinking about them and what they would mean – particularly as they relate to safety.
And when they do, they invariably think about how vehicles are currently regulated as a starting point. We envisage perhaps more regulation, standards and rules – because AVs are more complex and complicated. But for every regulation, standard and rule, we take responsibility away from the manufacturer.
Why?
Because all the manufacturer needs to do is ensure that their AV meets each regulation, standard and rule for them to not be liable for subsequent accidents (this is a simplistic interpretation to be sure … but satisfactory for the sake of this article).
Is this desirable?
Is this possible? [Read more…]
Weibull analysis is a tool that is used for characterizing the behavior of a data set. The value of characterizing a data set is being able to make predictions of failure rate for the same or a similar population. Input to the Weibull analysis is time to fail for all failed units and running time for operating units. The assumptions for the data set are critical to ensuring the right information is included in the analysis. This may include root cause analysis of the failures so they can be characterized as wear-out or use stress related. It would be beneficial to separate these two data sets because their characterization and behavior will be quite different Weibull factors. [Read more…]
If you had to section the history of reliability into only two periods I believe the dividing point would be around 1950. The first section, stone age to 1950, the “Robust” era; 1950 to today, the “Margin” era. In the robust, era reliability concerns were addressed by creating a design that was orders of magnitude stronger than required, “over-engineered”. This protected against the variability of fabrication, use, and environment. If it was made sloppily with low tolerances, it still worked; Used for an unintended purpose, still worked; Left out in the snow, dropped in the river, run over by a horse, buried in the sand; still worked. [Read more…]
I wonder how many product tests have been undertaken and nothing has been done with the results? Maybe development activities have moved on before any results are available? Maybe the test results didn’t provide the answers that were needed? Maybe the test wasn’t focused on the critical issues. In other words, cost, time and resources were wasted.
I will present a better way to ensure value is delivered and test results are acted upon. [Read more…]
Mission profiles are fundamental to any reliability prediction being valid. Without clearly defined environmental and use profiles there will be a long chain of inaccuracy that accumulates into significant errors within a product. 
This is what occurs at the following stages, or tools, if the mission profile or environment profile changes after its completion. [Read more…]
Do they design reliable products? Or Do they guide the development of reliable products?
It’s some mix of course. It depends on the process for the organization they operate in. I will point out that neither extreme works. I am often surprised with how many organizations I see that still have the 1950’s model of ” Design it and then give it to the reliability team to make it reliable.” I still don’t believe there is a single person in any engineering role in any engineering organization that believes that works.
That is what one of my old mentors used to call a “window dressing program”. No one believes it actually helps the product but you get to take your customers around your facility and show them all the great testing you are doing (SILENT END OF SENTENCE ” on out of rev parts and in a program phase where results can’t be implemented.”). [Read more…]
Understanding the reliability stakeholders in an organization is an interesting exercise.
Who are they?
It’s easy to look at each of those and say “They all could easily get by and appear successful even if a product has moderate to poor reliability”. You could also state that ” Reliability is a key factor to success in their role” [Read more…]
This is the bathtub curve we are often shown.
This is what a real bathtub curve looks like. [Read more…]
I posted an article recently by Bloomberg on the Defense Department’s recent disclosure of the escalating support cost of the F-35 Joint Fighter Jet. With over 3,700 views, it was the most read of my posts. The original article on escalating F-35 reliability costs can be read at this link
I posted the article with the comment: “Once a test engineer working for a large DoD contractor once told me at a reliability conference, ‘These new reliability development techniques of HALT and HASS would be a lot easier to implement if spare parts and service did not constitute 60% of the total program profits.’ That was not the first time I have heard a similar comment from a test or reliability engineer or manager working in the defense industry. I believe these engineers working on the reliability end of the programs said these concerns me out of frustration. [Read more…]
Talking is not the same as a discussion or conversation. Talking is one direction only. If two people are talking, they are talking at each other.
A discussion is two way. When two people have a discussion information passes both ways, both speak, both listen.
As an engineer, there is plenty to discuss. We work with others to find solutions, make compromises, determine optimizations, and finish projects. We need to share our knowledge and insights, as well as learn from others.
You can learn to foster true discussions and minimize simply talking at one another. You can take steps to enable the give and take exchange of a discussion. [Read more…]
Autonomous Vehicles (AVs) are still futuristic – but there are plenty of people are thinking about them and what they would mean – particularly as they relate to safety. And when they do, they invariably think about how vehicles are currently regulated as a starting point.
We envisage perhaps more autonomous vehicle regulation, standards and rules – because AVs are more complex and complicated. But for every regulation, standard and rule, we take responsibility away from the manufacturer.
Why? Because all the manufacturer needs to do is ensure that their AV meets each regulation, standard and rule for them to not be liable for subsequent accidents (this is a simplistic interpretation to be sure … but satisfactory for the sake of this article).
Is this desirable? Is this possible?