Reliability improvement of moulded case circuit breaker using Design for Six Sigma

PurposeThe purpose of this study is to develop a systematic approach by demonstrating the Design for Six Sigma (DFSS) approach for reliability improvement of moulded case circuit breaker (MCCB) (current rating 250A).Design/methodology/approachIn this study, the Define, Measure, Analyze, Design and Verify (DMADV) methodology of DFSS has been used to improve the reliability of MCCB. Mechanical endurance test (MET), project risk management, customer-based product development (PD), and other tools and techniques are used appropriately in DMADV methodology for improving the reliability of MCCB.FindingsIt has been observed that the reliability of MCCB has been improved from 61.76% to 98.17% for 20,000 operating cycles by implementing suggested improvement measures and the Weibull distribution is the most suitable distribution for reliability analysis of collected data.Research limitations/implicationsThis study considered only the aspects of DMADV methodology of the DFSS approach and does not cover other PD approaches such as lean and green PD.Practical implicationsThis study clearly shows an enhancement in the reliability of MCCB which further leads to an increase in the warranty period. This will attract more customers and enhance business.Social implicationsThe improvement in the reliability of MCCB would significantly reduce fatal accidents ensuring workplace safety in the industry.Originality/valueThe originality of this study is the reliability assessment using degradation analysis in the design phase of the DMADV process to predict failure during design verification.