Environmental stress screening
From Wikipedia, the free encyclopedia
Environmental stress screening (ESS) refers to the process of exposing a newly manufactured product or component (typically electronic) to stresses such as thermal cycling and vibration in order to force latent defects to manifest themselves by failure during the screening process. The surviving population, upon completion of screening, can be assumed to have a higher reliability than a similar unscreened population.
Developed to help electronics manufacturers detect product defects and production flaws, ESS is widely used in military and aerospace applications, less so for commercial products. The tests need not be elaborate, for example, switching an electronic or electrical system on and off a few times may be enough to catch some simple defects that would otherwise be encountered by the end user very soon after the product was first used. Tests may include the following:
♦ Temperature variations
♦ Vibration tests
♦ Pressure
♦ Flexibility tests
ESS can be performed as part of the manufacturing process or it can be used in new product qualification testing.
An ESS system usually consists of a test chamber, controller, fixturing, interconnect and wiring, and a functional tester. These systems can be purchased from a variety of companies in the environmental test industry.
The stress screening from this process will help find infant mortality in the product. Finding these failures before the product reaches the customer yields better quality, lower warranty expenses, and happier customers.
