Agent-based analysis of picker blocking in manual order picking systems: Effects of routing combinations on throughput time

Order picking is one of the most labor- and time-consuming processes in supply chains. Improving the performance of order picking is thus a frequently researched topic. Due to high cost pressure for warehouse managers the space in storage areas has to be used efficiently. Hence narrow-aisle warehouses where order pickers cannot pass as well as several order pickers working in the same area are common. This leads to congestion which is in this context referred to as picker blocking. This paper employs an agent-based simulation approach to investigate the effects of picker blocking in manual order picking systems with different combinations of routing policies for three order pickers in a rectangular warehouse with narrow-aisles. Results indicate that the best combination in terms of throughput time for three order pickers in a rectangular warehouse with blocking considerations is Largest gap (picker 1), Largest gap (picker 2), and Combined policy (picker 3).