A condition based maintenance simulation model for controlling the yield of pick and place machines

The scope of this work is to improve the production yield of a series of Pick and Place machines, the process is characterized by a high value of basic components, and therefore, eventually obligating rework of all refused units caused by defective assembling, causing high costs for the reworking. In literature there are models that base themselves on calculating the probability of different factors that vary the yield. The differnent studies conductied in this sense have not given positive results, since none of these models have considered technical parameters of the machines condition correlating it with the defectiveness of the assembled units at the end of the process. In this work we have proposed a condition based maintenance simulation model, which is able to determine when it is economically conveinent to make a preventive maintenance intervention on the machine in function of the number of refused units per unit of time produced by the process. The model that we have considered is a multithreshold model, which means that it consideres the possibility, once that the process line is stopped for preventive maintenace, to intervenue even on other machines, these interventions will be called opportune maintenace. The proposed model has clearly demostrated to improve the efficience of the process respect the nowaday, experienced based, management, but also respect a model based on the optimizing of the processes yield present in scientific literature.