The HASS development process

The advent of HASS (highly accelerated stress screen) into the marketplace has enabled scores of manufacturers to dramatically reduce the number of production related failures from being shipped into their customer's hands. HASS is a screening process that uses accelerated techniques to uncover manufactured product weaknesses and flaws. The process requires the use of the HALT (highly accelerated life testing) results, and other product specific information to design the initial profile, and then to tune it for optimal effectiveness. This paper presents the HASS development process as it was applied to a client's uninterruptable power supply (UPS) product. This process is presented in a systematic approach to demonstrate the methods employed to create an effective screen.