Reliability HotWire: eMagazine for the Reliability Professional
In this issue:

Issue 6, August 2001

*Hot Topics
*Reliability Basics
*Tool Tips
*Hot News
*From The Edge
*Put Yourself on the Hot Seat

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Hot Topics  
Reliability Allocation and Optimization
During the process of developing a new product, the engineer is often faced with the task of designing a system that conforms to a set of reliability specifications. The engineer is given the goal for the system and must then develop a design that will achieve the desired reliability of the system while performing all of the system's intended functions at a minimum cost. This involves a "balancing act" of determining how to allocate reliability to the components in the system so the system will meet its reliability goal while at the same time insuring that the system meets all of the other associated performance specifications.

In this article, we will look at how a cost function can be defined that will allow for the optimization of reliability within a system design.

To read more, see 

Reliability Basics  
The purpose of this section is to offer background and advice to the novice reliability engineer.

Sources of Reliability and Life Data
Part 2 - Field Data
While reliability testing is vital to the implementation of a reliability program, it is not the sole source of product reliability performance data. Indeed, the data received from the field is the "true" measure of product performance, and is directly linked to the financial aspects of a product. In fact, a great deal of field data may be more finance-related than reliability-related. However, given the importance of the link between reliability and income, it is important to insure that adequate reliability information can be gleaned from field performance data. In many cases, it is not too difficult to adapt current field data collection programs to include information that is directly applicable to reliability reporting.

To read more, see 

Tool Tips  

The Tool Tips section addresses helpful hints and frequently asked questions about ReliaSoft software products.

  • Is there an easy way to align the blocks in BlockSim?

  • How do I avoid having borders on my printed plots in Weibull++?

To read more, see

Hot News
*Announcing the Release of ALTA 6 and ALTA 6 PRO - After years in development and with great anticipation from the quantitative accelerated life testing community, ALTA 6 PRO is now available. For the first time ever, a software tool for accelerated life data analyses with time-varying stresses is now available. This product testing strategy, if applied correctly, will significantly reduce time-to-market, development costs and warranty expenses. For more information, see

*Upcoming Seminar in Tucson, October 15 -19 - An upcoming ReliaSoft "Master the Subject, Master the Tools" seminar will be held in Tucson, Arizona from October 15 - 19, 2001. Topics for this five-day seminar include life data analysis, accelerated life testing, and system reliability, maintainability and availability. For more information on course content and how to register, see

*Weibull++ MT: Reliability analysis package specifically for manufacturing and process engineers  - ReliaSoft has been working closely with the American Institute of Quality, Ford Motor Company and representatives of the machine tool supplier community to develop an industry-specific version of Weibull++. In July, ReliaSoft released Weibull++ MT, a life data analysis package specifically geared for those involved in plant maintenance or process reliability. In addition to all of the great functionality found in Weibull++, Weibull++ MT has special input and tracking methods for data specific to those interested in the reliability of manufacturing and production processes. For more information, see
  *Advanced accelerated testing analysis training available with "QALT Boot Camp" - ReliaSoft will begin offering an intensive three-day course on advanced topics, concepts and applications of quantitative accelerated life testing (QALT) with its "QALT Boot Camp." This seminar covers advanced topics in accelerated test data analysis such as time-varying stress and multiple stress testing. The next QALT Boot Camp will be held in Tucson, AZ November 14 -16, 2001. For more information on course content and how to register, see
From the Edge  

Every quarter, ReliaSoft publishes Reliability Edge, a printed journal that includes articles and information related to the field of reliability engineering. Articles of interest in the current edition:

  • Cumulative Binomial for Test Design and Analysis - Reliability engineers are often called upon to design demonstration tests in which few or no failures are anticipated. However, in order to design a truly effective demonstration test, a certain amount of knowledge about the characteristics of the product are needed and this information is not always available. Fortunately, the cumulative binomial distribution can be used to help reliability engineers design tests and analyze results without a great deal of prior knowledge concerning the failure distribution of the product. See
  • General Log-Linear Model for Accelerated Life Data Analysis - Decreasing development cycle times have increased the popularity of accelerated life testing for obtaining life data. However, many models limit the practitioner to the use of one or two stresses. The general log-linear model (now available in ALTA 6 PRO) allows a much greater degree of flexibility than many other models, allowing the user to incorporate multiple and non-quantitative stress inputs, that will allow for more powerful analysis of accelerated life data. See
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