Text version of the page

Highly Accelerated Life Testing(HALT) and Highly Accelerated Stress Screening (HASS)

Advanced Input Systems’ Philosophy: If you don’t have time to break it in the beginning you’ll have plenty of time to fix it later

HALT It is amazing how some products hold up in the real world. Used over and over again they validate their purchase price by providing reliable service over the test of time. Maybe you have felt the heat of summer expended into the interior of your car on a hot day and watched the worst of the snowy winter work on the exterior of the same automobile—yet thatcar still looks reasonably new; as if not affected. In reverse,it is such a disappointment when purchases tend to deteriorate much faster than they should. For most of us the operation of the failed device was under normal use and not abusiveoperation—meaning nothing beyond what the manufacturer would consider ordinary operation was expected in its function.So some devices failed and some did not. Why is this so? Whatdo some manufacturers perform in the way of testing / design services that distinguish them from others in the marketplace?Very likely the quality and ruggedness that you see in certainproducts is a result of some manufacturers performing (Highly Accelerated Life Testing) and HASS (Highly AcceleratedStress Screening). These processes differ in focus from each other but both are used to uncover problems through the means of time compression. In other words, HALT and HASSuse much higher stimuli than would exist in the field with theresult of forcing failures or revealing design flaws in the device in significantly less time. This allows a company to see how theirdesign would hold up “over the years” without having to wait that long. Defects are uncovered in the space of hours andobserved with the purpose of making ongoing corrections. These defects are then monitored, classified according to their nature and corrected. Samples of the corrections that can be made are improvements to the assembly process, making mechanical revisions to the design to remove stress or inherent design flaws or revising components that are not performing according to their advertised potential.There is always the push for getting projects done in the leastamount of time and refinements are made to streamline thedevelopment process as much as possible. In an effort to get aproduct to market expenses are watched very carefully by allconcerned. This testing is one corner, however, that cannot becut in an effort to meet budget or time considerations. Theresults of HALT / HASS testing have proved to be too valuableto most major manufacturers to skip; we have also seen the

The focus becomes high qualityand unsurpassed product value through test, analysis, and re-engineering.