A Preliminary study of the performance of Bucket Brigades when dealing with multiple aisles in warehouses
This paper presents a model and simulation that aims to compare the performance of the order-picking algorithm known as bucket brigades when dealing with multiple-aisle systems. In order-picking operations, the majority of the previous research works have applied bucket brigade over a single-line system. However, a realistic scenario involves a warehouse with more than one aisle. The contributions of this research work are: (1) an updated literature review using a state-of-the-art-matrix; (2) an extension of the normative bucket brigade model is presented. The proposed three-worker model introduces additional set of rules which copes with the different scenarios that can take place in a multi-aisle system. In the forward rule, workers move forward with their work until their successor takes over. If all items of an order get picked before a successor can take over, the worker proceeds to ship or if the successor is busy, the worker passes and moves forward. In the backward rule, if worker 2 or 3 finishes an order, they go back to their predecessor and take over their work. If worker 1 finishes (s)he goes back to start a new order. Both the single-line bucket brigade and the multi-aisle warehouse models were implemented using ProModel. (3) A comparison between these two was conducted in order to analyze the difference in performance in terms of worker utilization and order cycle time; (4) a sensitivity analysis was performed to test the multi-aisle model and how it changes when the number of workers is reduced and when the work content is increased.