A method to choose between carton from rack picking or carton from pallet picking

In a manual picker-to-parts picking warehouse, a usual approach is to divide the whole stocking area in two different zones, the reserve and the forward areas. The dimensioning of the forward area, which is dedicated to picking activities, has an important impact on the overall performance of the picking system. Indeed, its size as well as the item allocation deeply influence the travel time of the operators on one side and the frequency of the refilling activities on the other. The present paper aims to provide a new method that can be easily used to assess the most suitable way of storing a product in the forward area, considering the possibility of keeping a product directly in a pallet or storing it in racks. Starting from simple data, such as the picking orders of the items to pick and their physical dimensions, as well as the characteristics of the warehouse, the method focuses on the comparison of the total times to define the Carton Pick from rack Convenience Condition (CPCC). The CPCC formulation and its application methodology allow to quickly establish which items should be stored on pallets and which on racks, with interesting impacts on space and time savings. This is shown also in the reported case study, the results of which prove the effectiveness as well as the easy and full applicability of the methodology, also in different warehouse contexts.