Effect of reworking on defective parts in a flexible assembly cell

Abstract

Consider a flexible assembly cell, consisting of a set of general-purpose machines, a finite-capacity local storage, a loading station, an unloading station and an integrated automated inspection station, where workpieces are processed according to the first-come, first-served dispatching rule, and the inspection station is capable of detecting (i) non- repairable defective, (ii) repairable defective and (iii) non-defective workpieces. This workstation is capable of processing workpieces belonging to the same family of parts, and is also capable of reprocessing the inspected defective repairable workpieces. In this paper, the performance of the workstation is modelled by anM/G/1/K queueing system with a Poisson arrival process, a buffer of sizeK, a single server, generally distributed processing time, the first-come, first-served queueing discipline and an instantaneous Bernoulli feedback mechanism. This performance model is developed to define the relationships among the loading, the processing, the inspection and the unloading operations. Finally, to be able to study the tandem behaviour of this workstation in an assembly-line manufacturing environment, the throughput process from the workstation is also identified.