LAUSR

Abstract Labor costs account for the majority of operating expenses for warehouses. However, the suboptimal labor allocation strategy reduces the warehouse operation efficacy significantly. Due to the unbalance workloads, the idle time is observed when the wave picking policy is adopted, which increases the average order flowtime. This paper presents the first study on the distribution center labor allocation with wave picking. Distribution center layout, batch picking routes, conveyor congestion, put-wall capacity and picking device capacity were all considered in the simulation model. The wait time, start time, and finish time of orders in the picking and the sorting area were recorded. The length of the queue on the conveyor and the idle time of each worker were recorded as well. According to the simulation results, the optimal labor allocation strategies under different total labor levels were found. The mathematical relation between best value of the average order flowtime and the number of workers helps the decision maker to determine the total labor levels.