Scheduling in the dynamic job shop under auxiliary resource constraints: A simulation study

Traditionally, job shop research has only considered constraints related to machine and labour availability. With the advent of flexible manufacturing systems and just-in-time manufacturing, practitioners have recognized the importance of auxiliary resources (e.g. tooling) in production activity control and shop scheduling. In recent years, it has been recognized that theory and practice based on labour-constrained job shops cannot be generalized to auxiliary resource-constrained job shops. This paper presents a study of scheduling in the dynamic job shop under auxiliary resource constraints. Local and look-ahead dispatching and resource assignment rules, and a global Contingency Based Scheduling (CBS) approach are developed and evaluated in a dynamic job shop constrained by auxiliary resources. Several traditional measures of performance are employed including root mean square of tardiness, average system time and percentage of auxiliary resource changes. As shop utilization increases, the study reveals that the CBS algorithm is the only scheduling mechanism that consistently provides high performance on all three measures.