Worker Scheduling in a Multi-depot Warehouse Employing Pick-pack Switching Policy

Order picking and packing are two essential operations in the order fulfillment process, where workers can be allocated and scheduled under different policies. This study focuses on a pick-pack switching policy in a picking and packing wave of a multi-depot warehouse to shorten its completion time. All workers are responsible for the order picking task at the beginning, and then some move to packing stations for packing. We formulate the worker scheduling problem and propose a simulated annealing algorithm initialized by a backward scheduling to effectively solve the problem within a short computational time. The experimental results demonstrate that the pick-pack switching policy accelerates the completion time of a wave compared to the monotasking policy. Additionally, our proposed algorithm provides efficient solutions, achieving an acceptable difference from the weak lower bound.