Highly accelerated life test
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A highly accelerated life test (HALT), is a stress testing methodology for accelerating product reliability during the engineering development process. HALT testing is currently in use by most major manufacturing organizations to improve product reliability in a variety of industries, including electronics, computer and is performed during the product design and manufacturing cycles.
Environmental stresses are applied in a HALT procedure, eventually reaching a level significantly beyond that expected during use.
Failure rate data used to characterize any device in a product must correlate with the stress levels in the product or application.
Temperature cycling and repetitive shock, power margining and power cycling are the most common forms of failure acceleration for electronic equipment. It is a method used in industry.
What is HALT?
Highly accelerated life testing (HALT) techniques are important in uncovering many of the weak links of a new product. These discovery tests rapidly find weaknesses using accelerated stress conditions.
An environmental chamber is required for HALT. A suitable chamber also has to be capable of applying pseudo-random vibration with a suitable profile in relation to frequency. The chamber should also be capable of rapid changes in temperature. 50 degrees C/minute should be considered a minimum rate of change. Usually electricity is used for heating and Liquid Nitrogen (LN2) is used for cooling.
Test fixtures must transmit vibration to the item under test, fixture minimizes resonance at specific frequencies. It must also be open in design or that uses air circulation to maximize ramp rates.
Monitoring and failure analysis
The equipment under test must be monitored so that if the equipment fails under test, the failure is detected.
HALT is conducted before qualification testing. By catching failures early, flaws are found earlier in the acceptance process, eliminating repetitive later-stage reviews.
- Staff (1998–2012). "What is HALT HASS » Performing HALT". Qualmark. Qualmark Corporation. Retrieved 10 June 2012.