A flow picking system for order fulfillment in e-commerce warehouses

Abstract

A flow picking system in which the existing picking list is updated in real time has been considered as an effective solution for e-commerce warehouses to increase order fulfillment efficiency. The pivotal issues of performance analysis of flow picking systems, and comparison between batch picking systems and flow picking systems are of great concern, both for academics and practitioners of warehouse operation management. In this study, we first develop analytic models to estimate the critical performance indicators of a flow picking system, including picking density and turnover time of an order. Second, we leverage the proposed models and real warehouse data to compare the performance of batch picking and flow picking systems through simulation. Our results show that a flow picking system requires fewer order pickers and shorter walking distances than a batch picking system in most scenarios, especially those with a higher order arrival rate to achieve the same service level. Our study can provide valuable guidelines to warehouse managers and decision-makers for choosing an order fulfillment solution by comparing a batch picking system and a flow picking system.

Keywords:

• Flow picking
• batch picking
• order picking
• performance comparison
• simulation

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (grant nos 71991462, 71572090), the Shenzhen Basic Research Programs (grant no. JCYJ20180306174223343 and JCYJ20190813172201684) and a grant from the Institute for Guo Qiang, Tsinghua University.

Notes on contributors

Peng Yang

Peng Yang is an associate professor in the Research Center for Modern Logistics at Shenzhen International Graduate School, Tsinghua University, China. His research interests include order picking, warehouse operations, automated warehousing system, and green logistics facility.

Zhijie Zhao

Zhijie Zhao is a master’s student in the Shenzhen International Graduate School and Department of Industrial Engineering at Tsinghua University. Prior to that, he received his bachelor’s degree from Huazhong University of Science and Technology in China. He research is concerned with order picking, modern warehousing and supply chain system.

Zuo-Jun Max Shen

Zuo-Jun Max Shen is the Chancellor’s Professor in the Department of Industrial Engineering and Operations Research and the Department of Civil and Environmental Engineering at University of California, Berkeley. He is also an honorary professor at Tsinghua University and a Center Director at the Tsinghua-Berkeley Institute at Shenzhen. He received his Ph.D. from Northwestern University. He has been active in the following research areas: integrated supply chain design and management, design and analysis of optimization algorithms, energy systems, and transportation system planning and optimization. He is currently on the editorial/advisory board for several leading journals. He received the CAREER award from the National Science Foundation in 2003.