Scheduling with tool switching in flexible manufacturing systems

Abstract

In our problem, there are a number of jobs to be processed on parallel computer numerically controlled machines. Each job requires a set of tools and the required tools must be loaded to process the jobs. The machines have limited tool magazine capacities and the number of tools available in the system is limited due to economic restrictions, which leads to the need for switching tools. We assume that the tool switching time constitutes a significant portion of total processing time and does not depend on the number or type of tools changed. The problem is to assign the jobs and the required tools to machines and determine the schedule so that the makespan is minimized. A mathematical model and a heuristic approach based on the decomposition of the problem are developed.