McLinn, James A. (1988, ASQC) J.A. McLinn and Associates, Minneapolis, MN
Each year new technologies emerge that require evaluation and test via a reliability program. Strategies for handling these technologies are necessary. Past practices may need to be modified for these situations. Specific examples of how to handle some of these are presented below. A general review of some of the principles of reliability should occur.
New technologies may consist of: something totally new, never previously used; or a more familiar technology used in a new way; or two previously dissimilar technologies joined. Examples of these with specific approaches follows.
One new technology is that of software reliability. This has become increasingly important since many hardware functions are being replaced by software control. In these situations the combinations of hardware and software must often be considered.
A second type of emerging technology is driven by the creation of new and more powerful microcircuits. The recent advances allows them to be used in ways not previously tried. One specific example is the use of microcircuits with hydraulics in control applications. Feedback, customer safety and parts derating will all become issues. Traditionally, mechanical and electrical systems have had different approaches to system reliability. This blending of the two leads to unique test and evaluation methods to measure reliability.
The last example is the combination of flexible circuitry and surface mounted components. Flexible circuitry has existed for more than 20 years. Surface mount, on the other hand, is much newer and still evolving. Reliability concerns for flexible circuits focuses on materials. It includes considerations of temperature extremes, storage, thermal cycles, humidity and harsh chemicals. Surface mount components are normally concerned with temperature cycles, shock, vibration, humidity, longevity and self heating. The combination of these two may focus primarily on a few critical areas. At this point life tests, failure modes, and Weibull graphs will become important.
This paper will detail some specific examples in each of the areas and discuss similar reliability questions and approaches. Care and planning in the specification, design, testing and analysis then becomes the basis of the approach strategy.