Availability evaluation of manufacturing systems using Semi-Markov model

摘要: Availability is a key measure of performance systems in general and manufacturing are no exception. The elements complex such as Computer Integrated Manufacturing CIM follow variable, i.e., decreasing or increasing failure repair rates. This creates difficulty their availability evaluation. Conventional methods, which predict based on past experience, inadequate for systems. Existing analytical simulation methods provide inaccurate estimate these assume constant rates, exponential distribution. To address this concern, paper suggests methodology evaluation using Semi-Markov model, considers variable carried out by first understanding the system structure identifying its elements; subsystem, assembly component at hierarchical levels subsequently states; failed, operating, etc. Based this, models developed each element various system. unique feature approach that it does Weibull distribution times lognormal times. solved an solution method to obtain steady-state probabilities states hence, availability. illustrated means case study conducted Vertical Machining Center VMC used automotive production plant.