AST systems perform various accelerated stress test methods such as Highly Accelerated Life Test (HALT), Highly Accelerated Stress Screen (HASS), among others. Each type of stress precipitates specific defects that might be missed by traditional testing methods and equipment.
Highly Accelerated Life Testing (HALT) applies increasingly higher levels of stress to force product failures. HALT uses multi-axis vibration and high thermal ramp rates significantly beyond the product’s normal use environment to expose product weaknesses quickly. Using high levels of stress causes a significant time compression and exposes the same failures experienced during normal use over a product’s lifetime.
Highly Accelerated Stress Screening (HASS) is a production quality screen that applies similar, but much lower stresses, to those used in HALT. HASS aims to verify that production units continue to be manufactured as designed and quickly detects component or manufacturing irregularities, prior to shipping large quantities of flawed product. This screen is “tuned” so that it detects weak products while still leaving several, if not many, lifetimes of field use in the shipped product. For more information about AST methods, read our AST Handbook.