Your Reliability Engineering Professional Development Site
In a recent blog post, Seth Goin discussed the need for ongoing investment to maintain infrastructure. Whether a road or building or even your own skills, it takes regular care to avoid system failures or obsolesce. [Read more…]
In hypothesis testing, we set a null and alternative hypothesis. We are seeking evidence that the alternative hypothesis is true given the sample data. By using a sample from a population and not measuring every item in the population, we need to consider a couple of unwanted outcomes. Statisticians have named these unwanted results Type I and Type II Errors. [Read more…]
Statistical process control, SPC, is a set of tools to enable monitoring the stability of a process. SPC is also the first step to checking process capability with measures such as Cpk. Many consider SPC a quality or manufacturing tool. Yet, having and maintaining a stable process is also essential to creating a reliable product. Let me explain why. [Read more…]
We can make a guess, some assumptions, or conduct an experiment. In fact, we use engineering judgment, and prudent assumptions to create our experiments that lead to understanding time to failure information. Accelerated life testing, ALT, is one of the most complex and important types of experiments we conduct. It involves samples, failure mechanisms, stress, measurements, and statistics. [Read more…]
In the situation where you have a sample and would like to know if the population represented by the sample has a mean different than some specification, then this is the test for you. Oh, you also know, which is actually rather rare in practice, the actual variance of the population you drew the sample. [Read more…]
Very few reliability decisions are made by reliability engineers. Yet, reliability engineers are asked many questions concerning reliability. How reliable will this design be for customers? How will the system likely fail? How many failures should we expect next month?
How you answer these and the many other questions received does impact the reliability of your product or system. The information provided those that ask reliability related questions, with useful and practical information, can make better decisions which improves reliability performance.
Carl and Fred discussing the principles of teaching reliability, whether it is sharing knowledge to a small number of people or formally instructing a larger group of engineers. ᐅ Play Episode
In system modeling and fault tree analysis (FTA) we use a set of similar calculations based on Boolean logic, the AND and OR gate probability calculations. Within FTA, the AND and OR gates are just two of many possible ways to model a system. Within system modeling, often reliability block diagrams (RBD) we model parallel and series elements of a system.
In order to do these basic calculations, we need to consider a few assumptions then proceed to the math.
An immediate purpose is to earn a living. You also may suggest the work is to improve the reliability of the product or system. Reduce downtime, reduce warranty, increase profit, etc.
That is fine for the overall purpose of reliability engineering work, yet in the day to day work, the specific task level, what is the purpose behind what we do?
One of the things I like about reliability engineering is the field has a stable set of tools and approaches with an ever-changing set of challenges. The process of conducting an FMEA or Root Cause Analysis hasn’t changed much over time. Meanwhile, with the advent of new designs, materials, assembly techniques, and higher customer expectations, we continue to face interesting problems. [Read more…]
Fred discusses a couple of noticeable trends affecting our profession.
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Risk is uncertainty. Will this work? How will this item fail? Is it safe? Risk is not limited to product failure, including brand topics such as market acceptance, regulatory approval, supply chain stability, international conflicts, and more. Reliability engineering tends to focus on product failure to perform as expected, and we must fit into the large context of risks facing any product or system. [Read more…]
The goal of this presentation is to educate the audience on options to prevent electronic equipment failure used in enclosed spaces from corrosion through preventative maintenance practices. As most know, the metals used in today’s electronics are processed but want to turn back to their original state as the iron components will oxidize, and the corrosion process begins. Adding humidity, vibration, temperature swings, and acid environments (such as being in a tire plant or downwind from a refinery) will accelerate the process. It is this corrosion and subsequent weakening or disfiguring of the metal that causes malfunctions and failures [Read more…]
Dick Moss, retired HP Corporate Quality and Reliability Manager, once mentioned there are only five equations necessary to be a good reliability engineer. He quickly listed four equations and, with a smile, said the fifth one is the one you need to solve the current problem. [Read more…]
The difficult part of creating this list of essential techniques is to avoid selecting just the most common. There is an overlap between essential and those commonly used, yet essential implies a technique is crucial—crucial in rare yet very important situations. The idea for today’s discussion is to focus on those vital few techniques that every reliability engineer must master. [Read more…]
