Blog - Accendo Reliability

Parametric versus Non-Parametric Life Estimations – Sacrificing Reality for Elegance

A parametric Life Analysis involves “forcing” or “imposing” a distribution’s parameters on a data set in order to obtain the “best fit”. However, it can lead to errors in results. The non-parametric estimation suggests that there are other approaches though not necessarily the easiest or “most elegant” ones. In the field of reliability engineering, we tend to like something so much that we use them in every “sauce”. A classic example is the Weibull Distribution. It has become so popular that Life Analysis is also known as a “Weibull Analysis”. As a reminder, the Weibull distribution is only one parametric distribution amongst a myriad of others, invented by Walodi Weibull in 1937. Dr Bob Abernathy’s New Weibull Handbook¹ quotes: “the Weibull distribution provides reasonably accurate failure and failure forecasts……”. Thus, parametric distributions are good enough but not perfect to make a decision.

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by Kirk Gray 6 Comments

No Evidence of Correlation: Field failures and Traditional Reliability Engineering

Historically, Reliability Engineering of Electronics has been dominated by the belief that 1) The life or percentage of complex hardware failures that occur over time can be estimated, predicted, or modeled, and 2) the Reliability of electronic systems can be calculated or estimated through statistical and probabilistic methods to improve hardware reliability. The amazing thing about this is that during the many decades that reliability

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by Mike Sondalini Leave a Comment

Show All The Total Losses of Breakdowns

A good way to change mindsets and behaviors toward preventing forced outages and stoppages is to show everyone in the operation the total business losses of breakdowns.

It is incredible what the total business losses of breakdowns can rise too. Plant and equipment breakdowns are ultimately due to having wrong thinking and doing wrong practices. In this response to an FAQ, I advise to tell your people the true costs of breakdowns. Let them share the pain and loss suffered by the business and start them thinking of better ways to care for their operating assets.

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by Greg Hutchins Leave a Comment

Risk Averse Risk Officers are Killing Organizations

Guest Post by Patrick Ow (first posted on CERM ® RISK INSIGHTS – reposted here with permission)

Businesses exist because they are formed by entrepreneurs. They exist to earn a return for the business owners and shareholders.

Organizations exist to fulfill a specific social purpose and to satisfy a specific need of society. The potential for creating value for their customers and stakeholders is a key motive for all types of organizations, including the public sector and not-for-profits.

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by Hemant Urdhwareshe Leave a Comment

DOE-2: Application of Design of Experiments for Spot Welding Process

Dear Friends, we hope you have seen our first video on Introduction to Design of Experiments DOE)! Here is my second video on DOE! I have illustrated a case study of DOE application to Spot Welding process! The Case study is about application of Full Factorial Design with three factors, each at two levels. The video assumes that viewers have seen our first video on Introduction to DOE.

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by Nancy Regan Leave a Comment

Are RCM Principles Complex?

Eighteen years ago, at a small restaurant in Bath, England, a former head of the Royal Navy’s RCM program said something very poignant to me. It answers this question.

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by JD Solomon Leave a Comment

Five Helpful Tips for Leading Reliability Assessments

Assessing critical infrastructure and facilities is essential for maintaining performance as systems age. Mid-level engineers are frequently tasked with leading a reliability assessment with limited training. The good news is that you don’t need to be a subject matter expert to be successful. But you do need a structured collaboration approach and a mental model to help you through the tough spots. Success rises and falls based on the quality of the facilitation. [Read more…]

by Fred Schenkelberg Leave a Comment

Graphical Analysis of Repair Data

With the kind permission of Wayne Nelson and Robert Abernathy, we are posting an article on the analysis of repair data. As you may know, the assumptions made when using simple time-to-failure analysis of repairable systems may provide misleading results. Using the analysis method outlined by Wayne is one way to avoid those costly mistakes.

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by Greg Hutchins Leave a Comment

ISO 31000 Monitoring and Review – Final

Guest Post by Peter Holtmann (first posted on CERM ® RISK INSIGHTS – reposted here with permission)

This article is the final of fourteen parts to our risk management series. The series will be taking a look at the risk management guidelines under the ISO 31000 Standard to help you better understand them and how they relate to your own risk management activities. In doing so, we’ll be walking through the core aspects of the Standard and giving you practical guidance on how to implement it.

In previous articles we’ve looked at the core elements of the risk management framework and the role of leadership and commitment, integration, design, implementation, evaluation and improvement more specifically. We’ve also briefly looked at the risk management process in a general sense, the importance of communication and consultation, how to set your scope, context and criteria, identifying, analysing and evaluating risks, and monitoring and reviewing risks. In this article, we’ll be looking at recording and reporting risks.

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by James Reyes-Picknell Leave a Comment

Getting results – Change Can be a Rocky Road

To get different results of any kind, we need to make changes. As human beings we are very good at change, but not so good at “being changed”. If we want it, it will happen. If we don’t want it, we will resist.

Physical asset performance is a result of having a robust and reliable design to begin with, the right maintenance executed the right way, and operation within the assets’ performance limits. In an existing operation, the design is fixed already. Maintenance and operations however, are not, and can often be improved, usually with considerable effort. That effort however, can be well worth it.

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by Mike Sondalini Leave a Comment

The Effect of Managers and Supervisors on Organizational Success

Abstract: Do the reliability math on organizational structure design, and in a militaristic silo configuration you’ll see that managers have a huge influence on their departments performance. But what is most surprising is that supervisors in silo groups have more than double their manager’s impact on their group’s success. Managers making poor and wrong choices will cause serious trouble. But supervisors who get decisions wrong cause catastrophe.

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by Ray Harkins Leave a Comment

A Primer on Acceptance Sampling Plans

In modern manufacturing, ensuring product quality is paramount. One of the fundamental tools employed to maintain quality standards is sampling plans. These plans provide a systematic approach to inspecting a subset of items from a larger batch, allowing for efficient and reliable decision-making regarding the acceptability of the entire lot.

In this primer, we probe the essentials of sampling plans, their types, and the trade-offs between sampling and 100% inspection. Because of their ubiquitous use in manufacturing, we will more closely examine attribute sampling plans, including single, double, and multiple sampling plans, and their applicable industry standards.

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by Hemant Urdhwareshe Leave a Comment

DOE-1: Introduction to Design of Experiments

Dear Friends, this video is created to provide a simple introduction to Design of Experiments (DOE). DOE is a proven statistical tool and is known to be superior to the conventional approach of One-Factor-at-a-Time of OFAT! In OFAT, one tries to optimize the settings of various factors one by one. But this has a major limitation of not getting information about interaction of the factors! DOE helps us to estimate effects of various factors along with their interactions! This is the first in the series of videos that we wish to create and share in near future. Our future videos on DOE will include practical application examples of DOE, analysis and interpretation, optimization using DOE, Fractional Factorial Designs. We will also introduce later to Response Surface Designs.

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by André-Michel Ferrari Leave a Comment

Defining Inventory Min-Max Levels

A better approach using RAM models

Traditional spare parts or inventory calculation methods involving Min-Max levels lack rigor, especially for critical equipment. Reliability, Availability and Maintainability (RAM) models provide a better approach to this calculation.

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by Pete Stuart Leave a Comment

Shaping Organizational Behavior

When conducting a Human Reliability Assessment (HRA), we use the terminology errors of commission or errors of omission. It behooves every professional to question why we focus on one metric in preference to all others in an objective and constructive manner in order to discern whether we are exposing our organization to errors of professional omission or commission. The other conclusion is that we are doing the right thing and this is also an empowering piece of knowledge.

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