Modeling and Analysis of a Re‐Entrant Manufacturing System

Abstract

Re-entrant manufacturing systems can frequently be found in semiconductor industries, where the same work systems are used repeatedly for different stages of processing. Due to feedback loops in the material flow, re-entrant manufacturing systems show complex dynamic behaviour making it difficult to predict or control the performance of the systems. The first part of the paper presents a dynamical model of a re-entrant manufacturing system. This model shows different qualities of dynamic behaviour, depending on the ratio between work load and system capacity. The under-loaded system has the properties of a quasiperiodic driven dissipative dynamical system. The over-loaded system shows dynamics between quasi-periodicity and chaos. The second part of the paper presents a simulation model based on a dynamical control concept. The simulation model consists of different modules containing the system parameters. The system variables – buffer levels and processing phases – indicate the state of the manufacturing process. This model will be used to develop, test and evaluate dynamic control methods and to investigate the influence of different control policies on dynamics and performance of this re-entrant manufacturing system. Contribution to the book “Nonlinear Dynamics of Production Systems” Submitted 14 July 2003 Contact person: Michael Freitag Phone: +49-(0)421-218 97 90 E-mail: fmt@biba.uni-bremen.de Scholz-Reiter, Pikovsky et al.: Modelling and Analysis of a Re-entrant Manufacturing System Page