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FRACAS

FRACAS

The Failure Reporting and Corrective Action System (FRACAS) is a closed-loop process whose purpose is to provide a systematic way to report, organize and analyze failure data. Implementation of a FRACAS has increasingly become commonplace within an industry. The requirement for implementation of some type of FRACAS within a DoD program was first established in 1985 with MIL-STD-2155. However, in 1995 that standard was reestablished with no changes to content as a handbook, MIL-HDBK-2155, and was recommended as guidance. Today, multiple software solutions exist that provide all the functionality required of a FRACAS. [Read more…]

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Reliability Allocations

Reliability Allocations

After the system has been drawn in block diagram form, subsystem and component reliability goals and targets are established. This is a common practice in the development of complex systems, particularly when different design teams or subcontractors are involved. Reliability allocation involves setting reliability objectives for components or subsystems in order to meet a system reliability objective and should occur in the initial stages of design or prior to designing major system upgrades. [Read more…]

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Derating Value

Derating Value

This example is based on a real situation. After a class on design for reliability, a senior manager declared that every component would be fully derated in every product (electronic test & measurement devices). Within a year the design team redesigned all new and existing products, with strict adherence to the derating guidelines provided in the class. A year after the class the product line enjoyed a 50% reduction in warranty claims. They learned about derating and a manager saw the potential value. [Read more…]

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ALT Value

ALT Value

Here is an example of how to determine the future value of a specific reliability task. Many of us face the challenge of how to justify spending product development resources to provide insights and information to the rest of the team. Accelerated life testing (ALT) is particularly difficult: It is time consuming, expensive, and at times statistically complex. Having a clear method to estimate the value serves your career and the organization well, as both benefit from the right investments.

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Reliability Knowledge

Reliability Knowledge

A recent forum post included the notion that many engineers and managers developing products or maintaining equipment have knowledge apathy concerning reliability. “They don’t care!” was the poster’s words. Has this happened? Have we lost the ability to care about reliability?

Reliability Understanding

In a course I teach on reliability engineering management I ask my students to find an advertisement using reliability as a central theme or claim. This isn’t very hard to do, and I’ve regularly been surprised at the range of uses advertising finds around the concept of reliability. ‘Reliable Movers’ claims to reliably and safely move your belongings to your new home. A reliable shotgun ammunition-loading device suggests each shell will fire reliably. And, many other advertisements use the basic concepts of consistent, repeatable, safety, and trustworthy via the term reliable or reliability. There is a common and good association with reliability. [Read more…]

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Reliability Management Terminology

Reliability Management Terminology

For Reliability Engineers to converse with one another and with non-technical people in an organization, it is necessary for the language of reliability to be widely understood. These terms form the backbone of a working vocabulary and should be well understood by Certified Reliability Engineers.

Availability: Fraction of time that a system is usable. Steady state Availability = MTBF/(MTBF+MTTR) [Read more…]

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Reliability Predictions

Reliability Predictions

If only we had a crystal ball or another device to predict the future. From the general wondering about the enemies next move, to the soldier hoping their equipment will work. In the corporate boardroom estimating the competitions next move, to the maintenance manager ordering spare parts, we have many uses for knowing the future.

We often look to past performance to provide an indication of the future. Has this mutual fund regularly provided adequate returns? If so, we predict it will going forward. And anyone that has reviewed mutual fund performance also has read or heard the admonishment to not use past performance to estimate future returns. Mutual funds, markets, business and battlefields all change and respond in sometimes unforeseen ways. [Read more…]

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Weibull Distribution

Weibull Distribution

A continuous distribution is useful for modeling time to failure data. For reliability practitioners, the Weibull distribution is a versatile and powerful tool. I often fit a Weibull when first confronted with a life dataset, as it provides a reasonable fit given the flexibility provided by the distributions parameters. [Read more…]

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Reliability Value

Reliability Value

What is reliability management? Reliability Engineering? Would a product design or an organization benefit with a focus on reliability management and engineering? What is the value of a focus on reliability?

Any organization, that develops and produces products, has resource limits. It may be talent, capabilities, time, funding, or some combination of these. Yet, the goal to create a product that meets customer expectations includes the concept of product reliability. The product should provide the expected functions over time, without failure. This expected product reliability occurs, even if the design requirements and advertising do not explicitly mention product reliability. [Read more…]

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Reactive and Proactive

Reactive and Proactive

Do you let events happen to you, or do events follow your designs and expectations? Are you a spectator or actor? Do you wonder about your product’s future or do you control your product’s future? Are you reactive or proactive?

Every reliability and maintenance program is a system. Every program has inputs, such as product testing results and field returns. Every reliability program has outputs, such as product design and production. In the most basic terms, a reliability program includes product specifications for functionality including expected durability. The program includes some form of design, verification, production and field performance. Given this basic lifecycle description, it is possible for two types of approaches to executing the product lifecycle. [Read more…]

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Good Mind

Good Mind

It is not enough to have a good mind; it is more important to use it well. — Descartes

Learning and Value

Over the past week, I’ve received a couple of questions about the pursuit of a graduate degree in reliability engineering and about preparing for the CRE. One question was particularly interesting – how will a reliability engineering graduate degree or CRE help my career? [Read more…]

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Variance

Variance

In another post, I started the discussion about variability and interquartile range. This is part 2 of that discussion and will focus on variance.

With rare exception, most distributions or groups of data require more than one parameter (or statistic) to fully describe both the location and spread (scale and shape) of the group of data. Is the data clumped tightly about some value, or spread out over a wide range. [Read more…]