Flexible process plans: their value in flexible automation systems

Abstract

This paper defines three classes of process plan flexibility and investigates one class, sequence, via simulation. Sequence flexibility is measured by parallelism and system performance measured by makespan and mean flow time. For a modified job-shop problem both measures had a linear improvement with increased sequence flexibility. When all sequence constraints are removed makespan improved by 33-5% and mean flow time by 26-2%. These benefits were found to decrease as the workload became more continuous and homogeneous. The results have significant implications for mid-volume, mid-variety production from product design and assembly to process design.