Mitigating Design and Production Risk with HALT, HAST, and HASS

Neill Doertenbach


Power and communications systems in a community, massive IT infrastructures in large, data-dependent corporations, launch vehicles for multi-million dollar satellites and cardiac pacemakers all share a common and critical design and implementation aspect – the need to understand and minimize the risk of failure. As the complexity of a system increases, understanding all of the ways it can fail can become a staggering task. The opportunities for residual, undetected risks to induce failures increases with system complexity and, paradoxically, with the cost and consequences of those failures. For a company designing complex equipment with high reliability requirements, reducing this residual risk is an ongoing challenge. By using HALT (Highly Accelerated Life Testing) and HAST (Highly Accelerated Stress Testing) in the early design phase of new equipment, and HASS (Highly Accelerated Stress Screening) in manufacturing, previously unrecognized potential failure mechanisms are identified and eliminated, reducing residual risk and increasing reliability. This presentation describes how HALT and HAST, used together, can, in a very short time, dramatically reduce residual risk due to design issues in a system. It then discusses the new risks that come with production, and how HASS can capture at-risk products to further increase operational reliability.