The Optimum Bucket Size for Master Schedule in the Factory with Bottleneck

Abstract

Today, the problems that all manufacturers face is how to shorten manufacturing lead time, and manufacturers that adopt make-to-order production systems have to make products whose specifications differ with each order. In such a situation, an efficient production planning and control system is required. The function of scheduling is to plan and control the flow of order from its arrival to its completion. Generally, the scheduling system is hierarchically composed of several sub-systems. The number of hierarchies differs according to the size of the company and the complexity of the products the company manufactures. However, it is necessary for the scheduling system to have the following four sub-systems at least. First of all, an upper sub-system that screens the order and determines its due date. A master schedule is then drafted by a subsequent sub-system. Next, master schedule is broken down into a detailed schedule by yet another sub-system. Lastly, operations are dispatched to appropriate workstations by the lowest level sub-system. In this study, we focus our attention on the master schedule. This master schedule is drafted by loading. One of the problems on loading is that the method to set the optimum bucket size is not made clear. The purpose of this paper is to propose an estimation method for the optimum bucket size in the event there is a bottlenecked workstation in the work center. The relationship between bottleneck and bucket size is made clear, and due to the relationship, the structure of the equation to set the optimum bucket size in the event there is a bottlenecked workstation in the work center is proposed.