Your Reliability Engineering Professional Development Site
All articles listed in reverse chronological order.
“When the number of factors coming into play in a phenomenological complex is too large, scientific method in most cases fails. One need only think of the weather, in which case the prediction even for a few days ahead is impossible.” ― Albert Einstein
“Prediction is very difficult, especially about the future.” – Niels Bohr* We have always had a quest to reduce future uncertainties and know what is going to happen to us, how long we will live, and what may impact our lives. Horoscopes, Tarot
The Business Skills of a Good Reliability EngineerKnowing how estimate sample size or create a Weibull plot is not enough today.
Just having technical skills, while essential, is not sufficient.
Having a master of business administration (MBA) may be helpful it is not required, yet knowing the warranty and brand cost per failure is essential.
You also need to know which analysis to conduct and how it fits into the larger program, organization, and how it impacts your customers. You need to know the business side of your work as well.
You need to understand the business connection as you create plans and finalize analysis. Each test proposed should include a business connection. Each improvement proposed has to balance with the other priorities and objectives and remain compelling.
I don’t know as I write this what is important to your organization today. It varies, even within an organization and over time. You do need to know what is important and why to become a good reliability engineer.
It is not enough to do what someone tells you to do. At first that may get you starting yet how you connect your work to adding value become essential. Practice finding the connection with every task.
Ask questions.
And, so on…
The idea is to find who needs what by when and why?
This helps you plan, focus and deliver what is considered important at the moment in your organization.
For a high volume consumer product sold during the holiday period, time to market may be the top priority. This is because a delay to shipping means the loss of sales for the year. Missing the deadline is not an option. Thus, your work as a reliability engineer has to focus on how you can minimize the risk to any delays.
Now, you know that finding a critical reliability issue late in the process may delay the program, therefore focusing on reducing the chance of a late discovery is your focus. Early testing and development work on the highest risk element may help you identify reliability risks that have a long lead time to test and evaluate.
For a industrial product with relatively low volume the time to market pressure is not as intense. In this case, the brand image may be paramount. Thus getting the initial units as reliability as customer expect becomes an overriding priority.
One of the issues with this situation is the lack of prototype systems to evaluate. You may not have the capability to test full systems in any quantity prior to to the start of production, if ever. Thus, you work to identify and characterize each potential failure mechanisms becomes critical. The ability to create a viable system model allows you to prioritize your work on improving the critical few elements that will impact system reliability performance.
Other priorities may focus on cost reduction, cutting edge feature sets, or ease of use. Your organization likely has a clear priority. It’s then up to you to connect your work in reliability engineering to that priority.
For each reliability task proposed or delivered what is the value it provides connected to the primary priority (or secondary priority) in a clear and concise way. If the task or activity doesn’t add value, why are you doing it?
In the high volume consumer product situation, reducing the risk of a shipment delay provide value. Let’s say you are proposing HALT early in the program. How would that add value? By potentially identifying design or manufacturing faults if discovered late in the program would delay the project, then you arguably reduce the risk of delays by some amount.
For the low volume complex equipment situation, a HALT would improve the ability of the team to find and solve complex issues that may otherwise go undetected. Again, HALT would add value. In each case there is not a hard and fast formula yet there is a clear step by step connection between the task and the value to the organization.
There are two steps here. One understand the business and customers to the extent that you clearly understand what is important. Second, articulate the value related to the business priorities for each reliability task or activity.
To see more examples and ways to show value, see the book Finding Value: How to Determine the Value of Reliability Engineering Activities.
Your skill at connecting your work to value enhances your ability to focus on what is important and necessary. Thus it helps your customers, organization and your career.
With the design FMEA complete, the equipment should have high inherent reliability. The equipment can then be installed in the plant, and provide a high level of performance to the business, at least initially. This is where Maintenance comes in. Maintenance can enable a low Life Cycle Cost, by preserving the reliability of the equipment. [Read more…]
If a human is going to build, install, monitor, use, operate, repair, or dismantle, then the design team must consider human factors.
According to Wikipedia
Ergonomics (or human factors) is the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data and methods to design in order to optimize human well-being and overall system performance.
You may have been tapped one morning and given the assignment. You may have pursued the role either via a university program or by simply applying for the position.
Now what? How do you start in this role? What are you expected to do? [Read more…]
Lifetime: Evaluation vs. MeasurementHow can we tell whether an iron is hot enough? The answer is obvious: We can measure temperature by using a thermocouple and a meter. But, in practice, we lick our finger and touch the iron. Sizzle…. Yes, it’s hot!
We know a priori the boiling temperature of water and we can evaluate the temperature of the iron. This method has a lower cost. [Read more…]
Products and equipment start with a design. The functions and performance occur or do not occur according to the capabilities designed into the system.
I learned early in my career, as a manufacturing engineer, that some products were much easier to manufacture (less yield loss) than others, and it was often the design of the product that made the difference. [Read more…]
Maintaining high reliability or availability is a marked advantage for any system. A system that achieves the ability to avoid system downtime due to a single failure event, is essential in many applications. Yet, the fault tolerant capability comes at a price.
A system that achieves the ability to avoid system downtime due to a single failure event, is essential in many applications. Yet, the fault tolerant capability comes at a price.
Here is a short list and brief description of fault tolerant design disadvantages:
The nature of a fault tolerance design is to continue to operate normally even with a component failure.
Thus if the ability to detect a component failure relies on a loss of function or capability, it may be difficult to detect the failure. This sets the stage for a second component failure to cause a system downing event. [Read more…]
A common and poor technique to gather field data is to count the number of returns by week or month. This can provide a graph showing the number of returns over time.
It hides information you need to understand your field failures.
Let’s take a look at a way to gather the same field failure data and retain the critical information necessary for time to failure analysis. [Read more…]
The Technical Skills of a Good Reliability EngineerThe fundamental technical skills, as I see it, have to include statistics and root cause analysis skills. This skill set is one of three broad areas introduced in the article, What Makes the Best Reliability Engineer?
I would say these are the minimum technical skills for a good reliability engineer. Able to calculate sample size requirements, understand a dataset, and correctly determine the root causes of a failure.
There are others skills that would be great to include, such as electrical, mechanical and software engineering, plus materials science, physics, and chemistry. Yet, what separates a good reliability engineer from other types of engineering is our ability to plan and analyze life tests and to truly understand how and why failures occur.
This is often considered the same as leaping tall buildings with a single bound with respect to skill level.
Few enjoyed their undergraduate statistics class and recently fewer campuses require a stats course. Statistics is the language of variation and is essential for our understanding of the world our products experience.
If every product met the exact specifications of the design and only operated in one set of environmental and use conditions, we would have fewer field failures. If every failure mechanism led to failure exactly the same way within each and every product, we would have far fewer field failures.
Variability may lead to elements of a product being out of spec, or drifting/wearing to an out of spec conditions, thus failing. Variability may also lead to changes in the stress/strength relationships, again increasing the number of failures over time.
The ability of a good reliability engineer to use available data and statistical techniques to:
Is just the start of our expected statistical prowess. We also need statistical skills to:
Your ability to use the right tool to quickly solve a problem may span statistical process control, hypothesis testing, regression analysis, and life data analysis all before noon. That may well be like stopping a speeding bullet level of skill.
You may need to master all these elements of statistics if you’re working as a lone reliability engineer, or rely on a trusted colleague is so fortunate. Either way you need to understand enough statistics to know when and how to apply this set of technical skills.
Failure mechanisms are hard science – even the human factors related failures. Failures occur because something occurs at an atomic, molecular, code or interaction level that precipitate an error or fault to manifest.
Your technical skill includes understanding the range of possible errors and faults that may occur with your product and how to avoid, minimize or mirage each one. It may not be possible to anticipate and fully understand every possible failure mechanisms, thus we focus on the most likely and common, plus continue to learn about those new (or interesting) failure mechanisms that appear.
A second element to this set of skills is the ability to deduce the root cause of a failure. Given a failure, you should be able to conduct the root causes analysis to determine the underlying failure mechanism and initiating circumstance. This permits the team to take corrective action that actually works.
The skill set includes
The root cause analysis skill may rely on tools like x-rays and thermal imaging tools, some operated by specialists, yet you need to know which tools to employ and how to interpret their results. It may be fun to explore failures in a well furnished failure analysis lab, yet you need to focus on solving the mystery of what caused the failure.
You also need to be well versed in how to proceed from the “crime scene” (or instance of failure location), through symptoms, to non-destructive and destructive testing. You need to build your “case” based on evidence and logic, plus a healthy dose of engineering knowledge of the fundamental elements involved.
If working as the lone reliability engineer, you certainly need to establish an ongoing relationship with a failure analysis lab. In other words, do not rely on your vendors, do the failure analysis work under your organizations control with your own lab or contracted facility.
Get the information your team needs to solve problems or to avoid future problems by exercising your technical root causes analysis skills.
To be good, I’m suggesting you have to have robust skills in statistics and root cause analysis. Do you agree? What else would you argue is essential to be a good reliability engineer?
Implementing a new reliability development paradigm in a company which is using traditional, standards-based testing can be a perilous journey.
It is especially true with introducing HALT (Highly Accelerated Life Test) in which strength against stress, and not quantifying electronics lifetimes is the new metric. Because of this significant change in test orientation, a critical factor for success begins with educating the company’s top [Read more…]
In the article, Hypothesis Tests for Proportion, the comparison is between a given value and the sample. In this case, let’s compare two populations. We take a sample which provides a proportion representing each population and determines if the populations are different from each other based on the two samples.
The exact solution uses the Binomial distribution, yet when np and 1 – np are greater than 5, then we can use a normal approximation for the test statistic and critical value. [Read more…]
Often time’s equipment is procured, setup and put into operation with a single focus on reducing the initial capital expenditure. This can be a fatal mistake as the reliability of the equipment is built into the design of the equipment. This called the inherent reliability. Once the equipment is designed and installed, there is little the maintenance department can do to improve the inherent reliability. [Read more…]
Fielded products fail day by day. Customers report these failures generally seeking a way to remedy this issue. Gathering the reported or returned products or confirmed failures is common practice.
Depending on the product a simple replacement or exchange may suffice. For other products, repair or a refund may be appropriate.
In general, and not always, when a product fails in the hands of a customer, the organization designing, manufacturing and distributing the product learns of the failure. [Read more…]
WIIFT and Reliability MeasuresWIIFT is “what’s in it for them”. Similar to what’s in it for me, yet the focus is your consideration of what value are you providing your audience.
As a reliability engineer you collection, analyze and report reliability measures. You report reliability estimates or results. Do you know how your audience is going to use this information?
Consider WIIFT when reporting reliability. [Read more…]