Reducing picker blocking in a high-level narrow-aisle order picking system: insights from a real-life spare parts warehouse

Abstract

New market developments force warehouses to handle a large number of orders within short time windows. Although research optimizing storage assignment and picker routing is extensive, there remains a gap between academic research and practice. Real-life issues, such as picker blocking, high-level storage locations, precedence constraints, and safety constraints, have been considered insufficiently while optimizing order picking planning problems. This paper goes beyond the current academic state-of-the-art by showing the effects of these real-life issues on order picking efficiency and explaining the importance of incorporating these real-life issues while planning order picking operations. Multiple horizontal and vertical storage assignment policies, as well as multiple routing policies are simulated with the aim of reducing travel and waiting times. The results of a full factorial ANOVA are used to formulate managerial guidelines to increase order picking efficiency in narrow-aisle systems to address the new market developments resulting in enhanced customer service.