Multiple perspectives on analyzing risk factors in FMEA

Abstract

As an important part of the Design for X tools, Design for Quality (DFQ) is used to reduce cost and improve quality of products while maintaining reliability in preliminary design phase. As a powerful tool to reduce and eliminate possible failures, failure mode and effects analysis (FMEA) is broadly applied in detail design phase. However, scholars have criticized the traditional FMEA model for several shortages. In the past decades, nearly all the FMEA methods have been presented to heighten the rationality of ranking results by considering the risk factors (severity (S), occurrence (O) and detection (D)) simultaneously. The simultaneous analysis of risk factors (RFs) may result in the ignorance of impact on failure modes from extreme RFs. In fact, different combinations of RFs may obtain more comprehensive risk information about failure modes. Thus, a novel FMEA classification method is proposed by combining risk factors in pairs (i.e., S&O, S&D and O&D) to conduct risk assessment which can avoid interaction effect caused by simultaneous analysis of risk factors. Specifically, the fuzzy adaptive resonance theory is used to conduct failure modes classification based on the assessment results of S&O, S&D and O&D obtained by the grey relational analysis. Finally, a real case study, i.e., the final assembly process of spark plugs, from an automotive manufacturer in China is adopted to clarify the advantages of the proposed method.