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QDD 031 5 Aspects of Good Reliability Goals and Requirements

5 Aspects of Good Reliability Goals and Requirements

Good reliability requirements are going to drive our design decisions relating to the concept, the components, the materials, and other stuff. So, the moment to start defining reliability requirements is early in the design process. But, what makes a well-defined reliability requirement? There are five aspects it should cover: do you know what they are?

We’ll describe what makes a good reliability requirement and examples of common (but not good) requirements.

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by Larry George Leave a Comment

Help! They Lost the Data

What can we do without reliability function estimates? FMEA? FTA? RCA? RCM? Argue about MTBFs and availability? Weibull? Keep a low profile? Run Admirals’ tests? Look for a new, well-funded project far from the deliverable stage?

Ask for field data; there should be enough to estimate reliability and make reliability-based decisions, even if some data are missing. Field data might even be population data!

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by George Williams Leave a Comment

7 Steps of Clean, Inspect, & Lubricate

Through daily inspections, cleaning, and lubrication practices we can measure, prevent, and restore deterioration to our equipment. The expectation is that a team is put together made up of maintenance, operations, and leadership employees to roll out strategy beginning with one piece of equipment. They will implement the following 7 steps:

Initial Cleaning
Eliminate sources of dirt and hard to clean & inspect areas
Create and maintain cleaning, inspection and lubrication standards
General Inspection
Operator Inspection
Activities standardized
Team Development and Operator Driven Reliability

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by Larry George 1 Comment

Estimation of a Hidden Service-Time Distribution of an M(t)/G/∞ Self-Service System

(This is chapter 5 of User Manual for Credible Reliability Prediction – Field Reliability (google.com), cleaned up and typeset for AccendoReliaiblity Weekly Update.)

The nonparametric maximum likelihood estimator for an M/G/∞ self-service time distribution function G(t) extends to nonstationary, time-dependent, Poisson arrival process M(t)/G/∞ systems, under a condition. A linearly increasing Poisson rate function satisfies the condition. The estimator of 1-G(t) is a reliability function estimate, from population ships and returns data required by generally accepted accounting principles.

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by Bryan Christiansen Leave a Comment

Using CMMS To Improve Asset Maintainability

Mature organizations seeking a competitive edge are familiar with the term Reliability Centered Maintenance (RCM). A maintenance philosophy encompassing predictive, preventative, and maintenance, RCM uses defined processes to find latent or hidden failure modes, customizing maintenance processes to maximize system performance. Most understand that the RCM philosophy enhances equipment availability through improved reliability, increasing annual earnings before interest, tax, and amortization (EBITDA). Yet, some businesses fail to understand that equipment availability comprises two crucial inputs, not one. Equipment reliability, yes, but also equipment maintainability. [Read more…]

by Christopher Jackson 1 Comment

SOR 685 Demonstration Testing

Demonstration Testing

Abstract

Chris and Fred discuss the whole idea of ‘demonstration testing’ … and how it may be ‘chronically’ overused or at least misunderstood. Heard of ‘demonstration testing’ and need to learn more?
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by Larry George Leave a Comment

User Manual for Credible Reliability Prediction

The ASQ Reliability Division (RD), copyrighted the 2003 monograph “Credible Reliability Prediction” (CRP) but lost all copies circa 2014. I pestered the RD to let me republish CRP, because people asked “How do I make credible reliability predictions?” Copyright reversion to authors is accepted practice when a publisher no longer supports a document.

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by Larry George 2 Comments

Credible Reliability Prediction?

ASQ Reliability Division published “Credible Reliability Prediction” (CRP) in 2003. Harold Williams, Reliability Division monograph series editor, wrote, “[CRP] …delineates statistical methods that effectively extend MTBF prediction to complex, redundant, dependent, standby, and life-limited systems… This is the first text that describes a credible method of making age-specific reliability predictions…. This monograph presents insights and information inspired by real applications and [still] not covered in contemporary reliability textbooks.”

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by Christopher Jackson Leave a Comment

SOR 664 The Words We Use Matter

The Words We Use Matter

Abstract

Chris and Fred discuss the different words we often use (and misuse) in reliability engineering. ‘Reliability’ has been used for hundreds of years to describe different concepts of ruggedness, robustness, strength, timeliness, trustworthiness and so on. But – reliability has a specific definition within reliability engineering. There are plenty of other examples of how words we use in reliability engineering can have multiple meanings – even when we think they don’t!
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by Larry George Leave a Comment

Nonparametric Forecasts From Left-Censored Data

“Component D” had some failures in its first 12 months. How many more would fail in 36-month warranty? ASQ’s Quality Progress Statistics Roundtable published the data and Weibull analysis. The data included left-censored failure counts collected at one calendar time. The Weibull analysis included actuarial failure forecasts. This article describes nonparametric alternatives to Weibull and quantifies extrapolation uncertainty. The nonparametric forecasts are larger than the Weibull forecasts. Alternative extrapolations of nonparametric failure rates from data subsets quantify uncertainty. [Read more…]

by Robert (Bob) J. Latino Leave a Comment

Defining & Achieving the Reliability Culture

“There is nothing more difficult to take in hand, more perilous to conduct, or more uncertain in its success than to take the lead in the introduction of a new order of things, because the innovator has for enemies, all of those who have done well under the old conditions, and luke-warm defenders in those who will do well under the new.”
– Niccole Machiavelli

This quote is appropriate when we seek a paradigm shift towards a proactive culture, after spending our careers trained to become the best ‘react-ors’ or responders, we can be. I encourage you to read this lengthy article to the end for a surprise and to ask you a couple of questions about your experience with reliability. [Read more…]

by James Reyes-Picknell Leave a Comment

We want it now and we want it cheap

These days most of us are used to instant gratification – we want it now and we want it cheap! When it comes to information, entertainment, finding your way around, and communications we more or less have it all at our fingertips. It’s also available to us just about anywhere. We can even order and pay for coffee to pick up on our way from the commuter train to the office – no line ups for delays. We can book houses, rooms, hotels, airlines, vacations, and rental cars at the touch of our fingers with apps that show us the cheapest options. [Read more…]

by Alex Williams Leave a Comment

Guide to Maintenance Management Terminology

It’s easy to become overwhelmed with the vast amount of terminology used to describe maintenance concepts. Even those who are familiar with various maintenance management terms know there is a lack of consistency among sources. This guide to maintenance management terminology serves to help teams better understand the differences between key phrases used in the industry. Browse through our maintenance glossary below. [Read more…]

by Larry George Leave a Comment

Want Field Reliability, Without Life Data?

Would you like the reliability of all your products and their service parts, without assumptions, in real environments, and with all premature failures, complaints, repairs, warranty expirations, preventive maintenance, changes, warranty extensions, etc.? Field reliability tells what really happens! [Read more…]

by Robert (Bob) J. Latino Leave a Comment

Root Cause Analysis: The Justification Game

In last month’s introductory article, we discussed some of the barriers to selling not only the concept of Root Cause Analysis (RCA) but also the recommendations generated as a result of these analyses. We also laid the framework for making better predictions by generating and accessing better data—namely predicting our Mean Time between Failure (MTBF) and Mean Time to Restore (MTTR) earlier and, therefore, implementing a fix faster.

Given this background, let’s explore how we can now justify conducting a RCA and implementing the recommendations as a result of the analysis. By and far, conducting a true RCA is viewed as luxury not a necessity. Think about the objections we hear when we offer the idea of gathering RCA teams. What follows is a list of common objections to RCA accompanied by rational justifications that any manager can employ. [Read more…]