ORDER REVIEW RELEASE AND LOT SPLITTING IN DRUM-BUFFER-ROPE/

The drum-buffer-rope (DBR) planning and control system is relatively n ew in the published literature. As such, many issues relating to vario us operating policies have yet to be resolved. In this paper, we look at three such policies. First we study selected order review/release ( ORR) methodologies that have appeared in the published literature to b e used as the rope component in DBR. Secondly, we study the impact of lot splitting by breaking process batches into numerous transfer batch es. Lastly, the impact of capacity balance between the bottleneck reso urce and non-bottleneck resources are modelled. A simulation model of an existing V plant that manufactures pliers is constructed. Results i ndicate that the appropriate choice of each operating policy is a func tion of the shop performance criteria felt to be important by manageme nt. No previous paper has studied the feasibility of using the various ORR methodologies in a DBR environment. We show that the performance of each is dependent on other conditions within the shop. Likewise, th e impact of lot splitting has yet to be studied. We found that splitti ng process batches into smaller transfer batches nearly always improve d shop performance criteria. Further, simulation results indicate that shop inventory levels necessary to achieve comparable service levels is a function of the capacity balance between bottlenecks and non-bott lenecks, i.e. capacity slack. As capacity slack increases, thereby red ucing capacity balance, shop inventory levels show a corresponding dec rease.