HALT - Highly Accelerated Life Test
HASS - Highly Accelerated Stress Screen
HALT & HASS are unique, accelerated product reliability testing methods focused on finding defects in products so they can be fixed before becoming expensive field issues.
- Unique because HALT and HASS are different from traditional design verification testing - different goals, different stresses, different results.
- Accelerated, because HALT and HASS reveal product failure modes in a matter of hours or days, as compared to traditional test methods that can take weeks or even months to find, if at all.
HALT and HASS, collectively referred to as Accelerated Stress Testing (AST), subject a product to a series of overstresses, effectively forcing product weak links to emerge by accelerating fatigue. Unlike traditional single axis vibration test methods or thermal only methods, an AST program requires specialized HALT/HASS equipment to render the required stresses - random six-degree-of-freedom vibration and rapid thermal change rates - in the combined environment necessary to drive out latent failure modes.
In HALT and HASS, stresses are applied in a controlled, incremental fashion while the unit under test is continuously monitored for failures. Once the weaknesses of the product are uncovered and corrective actions taken, the limits of the product are clearly understood and the operating margins have been extended as far as possible. Result? A much more mature product can be introduced much more quickly with a higher degree of reliability.
Unlike DVT (Design Verification Testing), the purpose of HALT is to determine the operating and destruct limits of a design - why those limitations exist and what is required to increase those margins. HALT, therefore, stresses products beyond their design specifications.
HALT provides engineers with the opportunity to improve product design, increasing its robustness and minimizing possibility of costly warranty services and expensive product recalls after release.