Reliability modeling of manufacturing systems with multiple repair modes

The technological level achieved by manufacturing systems in recent years has caused an exponential enlargement of problems to be faced by management, such as cost minimisation, reliability and maintainability allocation, diagnostic system design. A newly developed model for assessing the impact of failures of equipment (subject to multiple repair modes) on system production capability is presented. It is based on the numerical simulation of delay times in the production flow and enables the analyst to consider alternative and realistic policies of failure management, different starting periods and ending procedures of a finite production phase. Some examples of series manufacturing systems, with and without buffer, are analysed and sensitivity analyses are performed to assess the influence of variations of reliability and/or maintainability characteristics of the equipment on the system performances.