Modelling flexible flow lines with generalized stochastic Petri nets

Flexible flow lines are a special type of dedicated FMS, composed by a number of stages, corresponding to different operations to be performed on the parts; each stage is composed by a number of identical servers. Simple criteria are currently used for the design of FFL. In this paper the author presents a Petri net model of FFL with the objective of capturing the processing variability. The model proposed allows a direct evaluation of the system performance in different physical configuration. This allows a designer, at an early design or start up stage, to dimension the system taking into account not only the nominal values of processing times but also all the uncertainties inherent in the operation of the line