Reliability Ques

Quanterion publishes an electronic version of “Reliability Ques” periodically as a means of keeping its customers and other interested parties up-to-date on effective tools, techniques, and approaches to improving the reliability, maintainability, and quality of products and systems.

Reliability: Costly, or Cost Effective?

October 26th, 2004

There are those who would argue that the costs of reliability activities associated with developing new products have little payoff. Whether we’re talking about commercial products or military systems, we don’t agree. Concepts like Life Cycle Costs, Total Ownership Costs, Reliability-based Maintenance, Performance-Based Logistics, and others clearly recognize the contribution of reliability activities in reducing…  Read More

Reliability Predictions: Parts Count, Part Stress, Pseudo Stress and Dormant

September 26th, 2004

Reliability predictions are an important tool for making design trade-off decisions and estimating future system reliability. They are often used for making initial product support decisions such as how many spares are required to support fielded systems. Inaccurate predictions can lead to overly conservative designs and/or excessive spare parts procurement resulting in added life cycle…  Read More

Reliability Knowledge? Who? What? Where?

July 26th, 2004

This article is the first in a series addressing the availability of reliability knowledge, who has it and how you can take advantage of it to improve products and systems. Despite a broad interest in reliability, there is a general lack of coordination of the efforts of many disparate organizations dealing with reliability issues.

In recent…  Read More

Warranty Cost: An Introduction

April 26th, 2004

Whether your company is marketing commercial products or selling to the Government, warranties are an important ingredient to competitive success. Effective warranty planning can ensure success, but lack of attention to cost analyses can spell disaster. This article is intended to introduce the basics of warranties and to identify sources for more information.

A warranty is…  Read More

Understanding Your Product Through Reliability Modeling

March 26th, 2004

A reliability model represents a clear picture of your product’s functional interdependencies providing a means to trade-off design alternatives and to identify areas for design improvement. The models are also helpful in:

Identifying of critical items and single points of failure
Allocating reliability goals to portions of the design
Providing a framework for comparing estimated reliability to product…  Read More

How Much Reliability is Enough?

February 26th, 2004

Reliability is defined as performance of a function over time, whether it applies to a commercial product or a military system. Commercial product reliability is usually driven by such factors as warranty cost goals, competitive marketing strategies, and liability concerns while the military wants to meet the operational needs of users while also meeting support…  Read More

System Spares – What’s the “Right” Answer?

December 26th, 2002

Manufacturers are often faced with questions such as:

How often will my system fail?
How many spare parts should I stock?
How confident am I that I will have enough spare parts?

We recently had a customer that had to answer these and other questions pertaining to warranty and system support issues. They were delivering a new system and…  Read More

Using Accelerated Life Testing to Assess Warranty Risk

October 26th, 2002

During a recent project, a question arose about the feasibility of providing a ten year warranty for a new system. The system consisted of a proven electronic assembly and 40 newly designed hybrid electronic modules. Warranty costs could be significant if reliability risks were not fully understood. The company producing the system wanted to be…  Read More

Which Variables Are Critical to Field Reliability? Design of Experiments (DOE) Can Help Optimize Your Design

August 26th, 2002

Engineers are often faced with the problem of optimizing a process that includes a number of input variables. It could be an analysis of a manufacturing process, or even an analysis of a business process. They’re often challenged to find ways to reduce warranty costs that result from field failures. For example, how can we…  Read More

Which Design is More Reliable? Weibull Provides Answers!

June 26th, 2002

Weibull Analysis is often used to analyze field or test failure data to understand how items are failing and what specific underlying failure distribution is being followed by failures that occur. One of our staff engineers was recently responsible for making a vendor recommendation for a limited life item that had a specified 5% minimum…  Read More