Warehouse picking or putting? A preliminary study to understand their applicability to fresh products

Among all warehouse operations, the preparation of customers' orders often represents a challenge. From one side, there is the need of fulfilling the requirements of the customers in short time windows; from the other side, there is the need of limiting operative costs. Moreover, when considering fresh products other aspects come into play, such as product quality and freshness, related to the time perspective, and the refrigerated storage, more linked to the cost dimension. In this paper, we propose the comparison of two alternatives for orders preparation, warehouse picking and warehouse putting, to understand when a configuration can be more appropriate than the other. First, we describe the two systems by highlighting strengths, weaknesses and differences. Then, we propose some mathematical formulations to measure time performance, occupied space and costs, also including energy consumption related to the storage of fresh products. The formulas are applied to real data, showing that the applicability of one system with respect to the other clearly depend on the number of orders per day and the number of stock keeping units.