HALT and HASS require specialized equipment and specialized training to achieve optimum product ruggedness and full financial benefits of accelerated testing.
#1) The Goal
Understanding that HALT and HASS are not intended to be a Design Verification Test (DVT) is critical to successful implementation of an accelerated reliability program. The goals of HALT are entirely different. The key difference? Unlike DVT, HALT is not a pass/fail test. There are no pre-established limits for HALT.
|HALT versus DVT
Different Purpose; Different Results
|Verifies that product meets specification||Stresses product beyond specification|
|Verifies that product will function in its intended environment||Stresses product until weak points fail|
|Is successful when product shows no failures||Determines functional and destruct limits|
|Is successful when failure modes are found and eliminated|
HALT and HASS for a different purpose and for different results - so that manufacturers can accelerate time to market with a more reliable and profitable product.
#2) Planning HALT
Successful HALT requires input from multiple disciplines; design engineering, test engineering, reliability engineering, manufacturing engineering and HALT system technicians. This HALT team will define test specifications, functional test requirements, methods of fixturing the product to the table, product components and/or locations to monitor with thermocouples, accelerometer placement, and define what constitutes a failure. Qualmark's Professional services can assist with HALT/HASS program development and management.
#3) Choose The Equipment
Qualmark's Typhoon series is specially engineered to produce the simultaneous extreme thermal and vibration energy necessary for accelerated reliability testing. See educational opportunities for becoming certified in accelerated stress testing.
The HALT process continues after completion of discovering failure modes. The next process is determining why the failure(s) occurred and deciding what should be done about them. Temporary fixes are made and the HALT process is continued until the fundamental limits of the product have been reached. By feeding failure analysis back into the design team, flaws can be eliminated, margins can be increased, and a more robust product developed.
HASS is a Highly Accelerated Stress Screen that is performed during manufacturing to ensure process integrity and to minimize marginal product getting released to the field. Most often, companies will implement HASS as a separate, second phase of accelerated reliability test integration.
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Qualmark partners with approved Accelerated Reliability Test Centers® across the globe that have both the equipment and technical expertise necessary to properly conduct HALT and HASS to improve your product. These centers perform a complete HALT on your product in a mere three to five days and provide a complete report for your design team.