Testing Articles (4)
Knowledge is power and we want our customers to have all the power over their products they can have. We will be continuously adding more articles.
These articles will cover many topics such as:
- HALT/HASS, AST (Highly Accelerated Life Test, Highly Accelerated Stress Screen)
- Vibration
- Humidity
- ESS (Environmental Stress Screen)
- Proof of Screen
- Design of Test
- Fixture Design
by Lloyd W. Condra, Hanse Environmental, Inc.
Environmental stress screening (ESS) is one of the most widely used of all accelerated reliability tests. It precipitates latent defects, which are detectable only with the application of stress. Latent defects are introduced into the product during manufacturing, since design-related defects should have been detected and eliminated by reliability-enhancement testing during the design phase.
Since the early 1980's there has been much discussion regarding various approaches and methods in the use of environmental stress screening and Halt/HASS to markedly improve product quality and life. Unfortunately, there was widespread misunderstanding and misapplication of the methodology . . . . and some still remains. Accordingly, we have listed the "Seven Deadly Sins of HALT/HASS".
The Problem
The short lifecycle of today's electronic products creates many pressures for rapid development and manufacture of new products, or product upgrades, in order to stay ahead in the competitive market place. Take for instance, the short model life of computers and printers. A new model appears every few months. Time-to-market is short, and customers expect the new models to work "out of the box" each and every time.
These pressures can result in compromised product development and/or manufacturing problems caused by part, process, and workmanship defects. The result is increased manufacturing costs, warranty costs, impacted profit margins, and sadly worse, customer dissatisfaction with resulting loss of market share.