Determining Production Schedule with Resource Constraints Using Drum-Buffer-Rope (DBR) Approach

Abstract

In wafer plants, product will be manufactured through same process with different setups and specifications. This special manufacturing process is described as re-entrant flows. In photo process of wafer manufacturing, products is also restricted to be processed through same machine in each reentrance to improve quality. This phenomenon will cause scheduling in photo process being complicated and is proved to be a NP-hard problem. This research develops a mathematical model for photo process to minimize the makespan. A feasible solution is achieved using DBR (drum-buffer-rope) method. The results are compared to the optimal solution that is achieved using branch and bound algorithm. Our results show that DBR based method achieves a near optimal solution in shorter time. The results also indicate that DBR method can be useful in production scheduling with resource constraints.