An efficient determination of order batching and design of picking sequence towards order-picking distance in a warehouse

Abstract

A frozen meat warehouse for import-export businesses is experiencing high unproductive travel distances during picking processes. This directly increases warehouse management costs due to a single unit-load picking protocol. Therefore, a new design for batch picking and picking sequence is crucial for improving warehouse performance. This research develops a two-step approach to address this problem: 1) Improving Warehouse Layout: Two methods, Class-based Storage and the Storage Location Assignment Problem (SLAP), are applied to investigate a new warehouse layout. The results of the first step show that SLAP outperforms other methods, reducing travel distance by 30%. 2) Designing Order Size and Picking Sequence: After establishing an efficient layout, the next step is to design the order size and picking sequence to further reduce picking distance and test sensitivity. Two approaches are employed: the Roulette Wheel Simulation method and a Genetic Algorithm. Performance testing of picking operations reveals that a new order size of 6 SKUs is optimal for batch picking. The designed picking sequence reduces unproductive picking distance by up to 30% compared to the traditional picking protocol.