An Assembly Scheduling Problem for a Flexible Manufacturing Cell with Arrival Times of Outside-Producted Components

Abstract

This paper considers an assembly scheduling problem for a flexible manufacturing cell (FMC), which consists of m dedicated machines and an assembly machine. There are n jobs to be processed in the FMC. Each of the dedicated machines produces a component of a job. In addition to m components, each job requires some other components purchased from outside. The assembly machine cannot start processing the job until both of all components produced in-house and those purchased from oustide are available. The objective is to find a schedule of the n jobs that minimizes the maximum completion time (i.e., the makespan). It has been known that the scheduling problem is strongly NP-hard even when m = 2. This paper proposes a greedy heuristic algorithm to the problem, and shows that it delivers a 2-approximation solution in O (mn²) time. The heuristic is also examined by means of numerical experiments, and the results are reported.