Order batching and sequencing problem under the pick-and-sort strategy in online supermarkets

The order picking and sorting-packing processes are important warehouses operations in online supermarkets under the pick-and-sort batch picking strategy. The buffer areas in the middle of these two processes play a buffering role, but the buffer size is limited because of storage facilities and finite room. Due to the differences between different batches, there may be too many batches blocking in the limited buffer areas which causes the stagnation of the picking process, or no batch in the buffer areas which causes the idleness of the sorting-packing process. This paper studies the order batching and sequencing problem with limited buffers with the objective of minimizing the total time of two processes for a given set of orders. We solve the problem with a modified seed algorithm.