Optimizing the number of failure modes for design analysis based on physics of failure

Abstract

Design for reliability requires a different approach from failure reporting and corrective action system (FRACAS) and test, analyze and fix (TAAF) both of which are tools for reliability improvement of already designed hardware. The physics of failure analysis approach should be used focusing on each failure mode separately. Through a step by step design analysis and test process, the number of potential failure modes should be reduced. As many failure modes as possible should be mitigated by appropriate design changes and the remaining failure modes should be controlled through adequate design stress vs. strength margins. The failure modes with insufficient margins (meaning high likelihood of occurrence in the time of interest) should be extensively analyzed and tested to ensure that they do not contribute to an unacceptable number of failures in the field. The use of this method requires that the equipment manufacturer also actively collect and list failure modes for previous products as well as for components, materials and processes.