ESS is process that applies a specific type of environmental stress, on an accelerated basis but within design capability, in an attempt to surface latent or incipient flaws. If undetected, these flaws would manifest themselves in the operational or field environment.The point of stress-screening is to cause failures by accelerate stress, not overstress. Thus, although the stress levels will usually be higher and more intense than seen by the unit in its usual operation, they must not exceed the design limits of the test article.
The most important role of ESS as an on-line manufacturing process is to ensure product quality by debugging a product of its early-life or infantile failures.