RCM implementation on plastic injection molding machine considering correlated failure modes and small size sample

Maintenance has become an important support for ensuring equipment availability, on-time deliveries and quality of products. In that sense, reliability-centered maintenance (RCM) could be used due to its basic characteristics like cost-effectiveness and accuracy. The RCM methodology is based on equipment reliability, which is estimated assuming that all failure modes are independent. However, in some cases, this assumption is not always satisfied. This paper seeks to show the effect of considering dependence for different failure modes; a comparison between traditional reliability models and copulas model is made. An injection molding process is considered for application in order to assess the proposed model and define a maintenance activities' program. Including dependence between failure modes in reliability estimation allowed 75% savings in the annual maintenance costs, which represent a direct benefit for company.