First Impressions

Note: This first article in the NoMTBF campaign was published on April 1st, 2009. Thus, we’ve been at this and making progress for a long time and come a long was since starting the NoMTBF campaign. I am looking forward to your comments, contributions, and suggestions.
Fred

At first, MTBF seems like a commonly used and valuable measure of reliability. Trained as a statistician and understanding the use of the expected value that MTBF represented, I thought, ‘Cool, this is useful.’

Then, the discussions with engineers, technical sales folks, and other professionals about reliability using MTBF started. And the awareness that not everyone, and at times it seems very few, truly understood MTBF and how to properly use the measure.

[Read more…]

by Fred Schenkelberg Leave a Comment

2015 Recommended References Survey Results

This is the first annual survey to find what you recommend for those preparing for the ASQ CRE exam.

See the full list of reliability references for the CRE exam, for reliability and maintenance engineers at Accendo Reliability. [Read more…]

by Michael Keer Leave a Comment

7 Proven Strategies to Protect Your Supply Chain

By Wayne Miller and Michael Keer

Reduce Risk and Prepare for the Unexpected

In today’s global economy, supply chain disruptions are inevitable. Companies must proactively plan for resilience and adaptability, whether due to geopolitical tensions, tariffs, component shortages, or factory challenges.

Product Realization Group’s veteran hardware and operations experts Michael Keer, Founder and Managing Partner, and Wayne Miller, New Product Development and Introduction, shared their insights on mitigating supply chain risk, drawing from decades of experience in manufacturing, operations, and supplier management. Below, we outline seven key strategies to safeguard your supply chain and keep your production on track.

[Read more…]

by Larry George Leave a Comment

Progress in USAF Engine Logistics?

I learned actuarial methods for forecasting and spares planning while working for the US Air Force Logistics Command in the 1970s [AFLCM 66-17 and AFM 400-1]. I am grateful for the education, and I am sorry to report that the USAF has reverted to MTBF management.

The US AFLC actuarial methods were developed for engine management in the 1960s by RAND Corp. [Giesler] They estimated age-interval failure rates and made actuarial forecasts of engine demands depending on the flying-hour program plan. An actuarial forecast is ∑a(s)n(t-s), s=1,2,…,t, where a(s) is actuarial failure rate conditional on survival to age s and n(t-s) is the installed base of age t-s. Periodic meetings consolidated engine lifetime and failure data into agreements on actuarial failure rates, for forecasting engine demands and for war readiness spares requirements.

The USAF actuarial methods assume constant failure rates within short age intervals, Poisson demands, and ignore variance induced by variable flying hours per aircraft in the flying hour program. I later figured out how to estimate actuarial failure rates for all engines, major modules, and their service parts, with or without life-limits and without lifetime data; I computed the distribution of demand forecasts, not Poisson. I offered to show AFIT faculty, AFOSR, AFRL, and RAND how to extend actuarial methods to all service parts [George, 1993].

[Read more…]

by Fred Schenkelberg Leave a Comment

MTBF and Mean of Wearout Data

MTBF is Just the Mean, Right?

A conversation the other day involved how or why someone would use the mean of a set of data described by a Weibull distribution.

The Weibull distribution is great at describing a dataset that has a decreasing or increasing hazard rate over time. Using the distribution we also do not need to determine the MTBF (which is not all that useful, of course).

Walking up the stairs today, I wondered if the arithmetic mean of the time to failure data, commonly used to estimate MTBF, is the same as the mean of the Weibull distribution. Doesn’t everyone think about such things?

Doesn’t everyone think about such things? So, I thought, I’d check. Set up some data with an increasing failure rate, and calculate the arithmetic mean and the Weibull distribution mean. [Read more…]

by Ray Harkins Leave a Comment

The Paradox of the Invisible Discipline

Early in my quality management career, while working at a small extrusion and fabrication company, I learned something important: bosses pay attention to the money. And if I focused on cost savings projects, I could stay on their good side.

Most of my cost savings efforts at that time focused on eliminating specific types of defects. After all, even a low-frequency defect—especially one that reaches a customer—can drive substantial savings once resolved. Other projects looked inward, targeting inefficiencies in our systems and practices. Lab procedures, control plans, and audit schedules tend to drift out of sync with the products and processes they’re supposed to control. So every now and then, a little system hygiene—an organized cleanup—can free up resources and allow you to reallocate attention to where it’s needed most.

It was during one of those hygiene projects that I stumbled into something I’ve since come to call The Paradox of Invisible Discipline.

[Read more…]

by Semion Gengrinovich Leave a Comment

Historical Data

The power of historical failure data is a gold mine of information for reliability engineers. It provides a window into the life cycle of products, revealing patterns and trends that can inform future designs and manufacturing processes. By analyzing this data, we can identify common failure modes, detect early life failures indicating quality or production issues, determine the onset of wear-out stages, and predict time to failure for similar products.

[Read more…]

by Mike Sondalini Leave a Comment

RCFA and 5-Whys Tips for Successful Use

When you do a Root Cause Failure Analysis or a 5- Why there are no promises that you will actually find the true root cause and fix your problem. Investigating the cause of a failure is fraught with traps, such as making wrong assumptions, insufficient evidence, misinterpreting the evidence, misunderstanding, personal bias and second-guessing. There are necessary issues you need to be aware of that affect the RCA and 5-Why methods, and there are some good practices that you can adopt to improve your chance of doing a successful analysis when applied to equipment failures.

[Read more…]

by Greg Hutchins Leave a Comment

Higher Education Disruption

If colleges were businesses they would be right for hostile takeovers, complete with serious costcutting and painful reorganizations.
US News and World Report

COVID has forced universities to do online teaching. What’s the value add of spending $70K (USD) for online instruction, when you paid for sports, in-class instruction, and the college experience? In 2021 and 2022, we’ll find out as university students who have been taught online for a year or even longer.

[Read more…]

by James Reyes-Picknell Leave a Comment

Today’s Gremlin – The White Knight

Today’s Gremlin – “The White Knight”, is a day-to-day hero, fixing what’s broken and returning the operation from panic. When things break, you really do need him, and he can be a hero, but couldn’t he be preventing those breakdowns?

The White Knight is the one you call when things have gone wrong. You need things fixed fast, regardless of the time of day, and he’s there for you. He works overtime if needed, he’s there when you need him, and he’s fast. Things do get fixed. But do they stay that way?

[Read more…]

by Joe Anderson Leave a Comment

The Power of Direction Setting

Leading with Purpose and Clarity

In any organization, the absence of clear direction can lead to confusion, inefficiency, and stagnation. Direction setting—the process of defining a vision, establishing goals, and communicating a clear path forward—is one of the most critical functions of leadership. When done effectively, it empowers teams, drives progress, and ensures that everyone is working toward a shared purpose.

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by Hemant Urdhwareshe Leave a Comment

Statistical Tolerance Stack-up

Dear friends, we are happy to release this 85th video in our channel ‘Institute of Quality and Reliability’! In this video, Hemant Urdhwareshe has explained the concept of statistical tolerancing tolerance stack-up! Conventional Extreme Value Analysis (EVA) can result in increased manufacturing costs! Statistical tolerancing is more optimistic method of analysing tolerances and can reduce manufacturing costs! Concepts of loop diagram, additivity of variances are also explained briefly in the video with a practical application case study of tolerance stack-up analysis.

[Read more…]

by Nancy Regan Leave a Comment

How to Set Condition-Based Maintenance (CBM) Intervals Using the P-F Curve

Welcome to Part 4 of our Reliability Centered Maintenance (RCM) Case Study, where we take a deep dive into Condition Based Maintenance (CBM). CBM, also known as On-Condition Maintenance, is a proactive approach that allows us to detect Potential Failure Conditions and take corrective action before failure occurs. In this video, I explain:

What Condition Based Maintenance is and how it works
The role of the P-F curve in determining CBM task intervals
A Real-life example of a CBM task
Why the P-F interval is used to set CBM task intervals
How CBM differs from Preventive Maintenance and other strategies

[Read more…]

by André-Michel Ferrari Leave a Comment

Reliability Engineering – Science of Pessimists?

Introduction

This is a rather depressing title for an article specifically on the topic of Reliability. After all, Reliability relates to the Probability of Success hence the contradiction.

However, the contradiction is not so much one as Reliability Analysis depends on having access to failure data. In other words, if the equipment does not fail, it might be difficult or even impossible to perform an analysis. Of course, we can source other types of data that are not failure records, but this is not the common approach.

[Read more…]

by Michael Keer Leave a Comment

14: Volume Manufacturing

By Mike Freier

The Journey to Volume Manufacturing and Beyond: Scaling Your Hardware-based Product

In the span of our idea-to-scale series, we’ve navigated through the various phases of transforming a hardware-based product idea into a market-ready product. We’ve explored the crucial stages of design, planning, development, as well as controlled introduction. Now, we arrive at the pivotal point of Volume Manufacturing, where we will learn how it can be leveraged to increase efficiency, improve quality and lower costs to effectively scale your business.

In this final segment, we turn our focus to scaling a resilient supply chain and revisiting key concepts from earlier segments. These include Contract Manufacturer (CM) selection, tooling and fixturing, communication, and business systems. We’ll also include additional insights into production forecasting, test, and logistics and repair, with a focus on quality, delivery and cost-effectiveness.

[Read more…]

by Semion Gengrinovich Leave a Comment

Can we Predict all Failures?

Predicting all failures in any system, including the automotive industry, is an inherently complex and challenging task. The inherent unpredictability of certain failure modes, coupled with the vast array of variables in operational environments, makes it impossible to foresee every potential failure. However, through strategic approaches and methodologies, it is possible to minimize major failures and reduce the infant mortality failure rate, thereby enhancing the reliability and safety of automotive products.

[Read more…]

by Fred Schenkelberg Leave a Comment

Is Using MTBF Habit Forming?

With Enough Reinforcement, MTBF Use Becomes a Habit

A habit you should examine and stop.

At first, I wondered if MTBF use was addictive, yet I thought that comparison would belittle the very serious issues of those with addictive behaviors. Using MTBF does not generally cause a person harm, while poor decision based on it might harm the organization.

I find those that regularly employ MTBF do so without thinking about it too much. If someone mentions reliability, they think MTBF. Automatically.

Habits help us reduce cognitive load and make our life simpler. For example, do you need to focus on how to put on your shoes every morning? I’m personally happy my habit skills allow me to remember how to drive safely without the intense focus required the first time I got behind the wheel.

Let’s examine how to tell if someone has the Habit of MTBF use and what you can do about it. [Read more…]