Assembly line sequencing based on Petri-net T-invariants

Mass production of goods with customer specific features is mostly carried out on production lines. Job-dependent processing times in the lines' individual work zones requires line sequencing in order to use the line to capacity. This paper presents a two-step method allowing fast sequencing even for large numbers of jobs and product types. The knowledge about the line characteristics and about the possible jobs is modelled using a Petri-net. The resulting model is independent of the set of jobs to be scheduled. Based on the Petri-net's T-invariants, a valid production sequence is efficiently determined for a particular job set. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.