Accendo Reliability

Your Reliability Engineering Professional Development Site

Home » Archives for Fred Schenkelberg » Page 41

Fred Schenkelberg — Thought Leader

Author of CRE Preparation Notes, Musings", NoMTBF, multiple books & ebooks>, co-host on Speaking of Reliability>/a>, and speaker in the Accendo Reliability Webinar Series.


This author's archive lists contributions of articles and episodes.

by Leave a Comment

How to Prepare for the CRE Exam

How to Prepare for the CRE Exam

The ASQ CRE exam is difficult. The individual elements of the body of knowledge are not in themselves difficult, it is just such a broad range of topics that mastering all the subjects is a challenge.

The CRE Body of Knowledge includes elements of leadership & management, testing & failure analysis, and basic & advanced & reliability statistics. Reliability engineers work across the spectrum of consumer product design to plant maintenance.

Depending on your experience you may have a wealth of experience with availability modeling and repairable system data analysis, and have little experience with design for reliability practices. [Read more…]

by 1 Comment

How to Connect Reliability Goals to Business Objectives

How to Connect Reliability Goals to Business Objectives

Reliability goals provide you and your team a focus for the reliability program. They provide a measurable way to design, test, and maintain systems that meet customer expectations.

A goal of any kind in a business is relatively easy to set and publish. They are not easy to entwine into the culture of the organization so the objectives desired by achieving the goal become a meaningful focus. A product development team may have hundreds of pages of specifications and a long list of priorities and objectives. Simple listing a reliability goal, no matter how clearly stated, may not be sufficient to garner the interest of your team.

Simple listing a reliability goal, no matter how clearly stated, may not be sufficient to garner the interest of your team.

[Read more…]

by 4 Comments

Common Mode Failures

Common Mode Failures

Common mode or common cause failures related to redundant systems where one cause can lead to the failure of otherwise redundant elements leading to system failure.

Elements which should fail independently are under some circumstances dependent.

When considering the probability of individual paths in a complex redundant system, take due care to consider the common mode failures which may have a higher probability than any single path in the system. [Read more…]

by Leave a Comment

Reliability Engineering is More Than Tools

Reliability Engineering is More Than Tools

Reliability engineering is a blend of disciplines from material science to asset management. We use problem-solving, design, maintenance, and statistical tools on a regular basis, yet that is not the only thing we do.

Having met a few engineers that define their role as a reliability engineer as conducting HALT or FMEA only, strikes me as to what most believe we do, or should do, as a reliability engineer. It is true that someone may specialize by choice or chance on one tool, yet even then is that all they do?

I don’t think so.

[Read more…]

by Leave a Comment

Create a Meaningful Environmental Test Plan

Create a Meaningful Environmental Test Plan

Create a Meaningful Environmental Test Plan

We often want to know if our product will work as expected in our customer’s environment.

Creating an environmental test plan that clearly shows weaknesses and strengths should be part of your program for each product.

Let’s explore the steps and resources you should consider when creating an environmental test plan for each product.

We will discuss why using standards or even the plan from the last program may not provide you meaningful information.

Understanding how your product responds to your customer’s environment provides the information for your team to make improvements and improve product reliability.
ᐅ Play Episode

by 3 Comments

OC Curve with Binomial Method

OC Curve with Binomial Method

The operating characteristic curve is useful to understand the capability of a lot sampling plan. It depicts a graphical relationship between the unknown lot’s defect rate and the probability of the specific sampling plan to accept the lot. Ideally, we want a sampling plan the correctly accepts good lots and rejects bad lots. [Read more…]

by Leave a Comment

Sources of Variation

Sources of Variation

We have statistics to describe the variation that occurs in our world. Statistics is the language of variation.

If each of your produced products were identical in every way to all products produced, with no variability, we wouldn’t be concerned with the effect of variation on the performance and reliability of our designs.

Yet, variation does happen and we have a range of tools to identify and minimize the naturally occurring variation. [Read more…]

by 11 Comments

Fault Tree Analysis 8 Step Process

Fault Tree Analysis 8 Step Process

Fault Tree Analysis (FTA) provides a means to logically and graphically display the paths to failure for a system or component. One way to manage a complex system is to start with a  reliability block diagram (RBD). Then create a fault tree for each block in the RBD.

Whether a single block or a top level fault for a system the basic process to create a fault tree follows a basic pattern. [Read more…]

by Leave a Comment

Break the “we’ve always done it this way” cycle

Break the “we’ve always done it this way” cycle

Break the “we’ve always done it this way” cycle

Reliability and test planning takes time and it’s easy to use the plan worked out for the last program.

Yet this doesn’t consider the new risks or technology or use conditions that impact product reliability.

If you find resistance as you propose improvements to the reliability plan or to the test plan, what can you do to gain acceptance?

If the source of resistance that what we did last time worked, why change, then what steps can you take to secure support for the needed changes?
ᐅ Play Episode

by 6 Comments

Benefits of Fault Tree Analysis

Benefits of Fault Tree Analysis

Is a logical, graphical diagram that organizes the possible element failures and combination of failures that lead to the top level fault being studied.

The converse, the success tree analysis, starts with the successful operation of a system, for example, and examines in a logical, graphical manner all the elements and combinations that have to work successfully.

With every product, there are numerous ways it can fail. Some more likely and possible than others. The FTA permits a team to think through and organize the sequences or patterns of faults that have to occur to cause a specific top level fault. The top level fault may be a specific type of failure, say the car will not start. Or it may be focused on a serious safety related failure, such as the starter motor overheats starting a fire. [Read more…]

by Leave a Comment

How to Break into Reliability Engineering

How to Break into Reliability Engineering

I’ve recently received a couple of notes from individuals looking at starting a career in reliability engineering. One is a student looking at a career path, another a working engineer with an interesting in reliability.

Both asked how to land a position given no reliability engineering experience.

Hum, I don’t know anyone that had reliability engineering experience before they got started working in reliability engineering. Not counting taking apart the family toaster and trying to repair it before Mom got home as a kid.

[Read more…]

by Leave a Comment

When to Make a Reliability Prediction

When to Make a Reliability Prediction

The easy answer is very often. Each time you want to know how long a product will operate. The accompanying question on how well the estimate will match actual performance makes the real answer more difficult.

We regularly and intuitively do reliability predictions all the time. When starting a car at the beginning of a trip, we estimate the ability of the vehicle to complete the journey. When we purchase a phone, we expect it to operate for at least two years (your expectations may differ).

During the design process, we may have formal or informal useful life expectations. It is not knowing if our decisions related to the design will fulfill the lifetime expectations that leads to the desire to know how well the resulting system will operate. We also may need to estimate warranty or maintenance costs, thus knowing what is likely to fail becomes important.

In general, knowing how long something will operate without failure provides the feedback we need to create a viable system that meets our business and customer reliability expectations.

In short, we do reliability predictions regularly to gauge is we are making good decisions. [Read more…]