Title: Order oriented slotting: a new assignment strategy for warehouses

Authors: Ronald J. Mantel, Peter C. Schuur, Sunderesh S. Heragu

Addresses: Department of Engineering, University of Twente, Enschede, The Netherlands. ' School of Business, Public Administration and Technology, University of Twente, Enschede, The Netherlands. ' Department of Industrial Engineering, University of Louisville, Louisville, KY, USA

Abstract: This paper deals with a new strategy for the assignment of Stock Keeping Units (SKUs) to storage locations in a warehouse, called Order Oriented Slotting (OOS). Given an empty warehouse, a set of orders to be picked and a routing policy, OOS stores the SKUs in such a way that the total time needed to pick all the orders is minimised. Unlike the Cube per Order Index (COI) slotting strategy which stores an item based on how frequently it is picked without regard to picking sequences, OOS aims to store items, that appear together in orders, close to each other. OOS can be formulated as an Integer Linear Programming model when the routing is S-shaped and when a Vertical Lift Module (VLM) is adopted. Given the computational complexity of the problem, we present several heuristics. Their performance is compared through a set of VLM test problems with different order characteristics. [Received 7 November 2006; Revised 17 March 2007; Accepted 18 May 2007]

Keywords: warehouse systems; storage allocation; slotting strategies; routing strategies; integer linear programming; ILP; heuristic search techniques; order oriented slotting; assignment strategy.

DOI: 10.1504/EJIE.2007.014689

European Journal of Industrial Engineering, 2007 Vol.1 No.3, pp.301 - 316

Published online: 25 Jul 2007 *

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