Batching of Precedence Constrained Order Picking Bins in a Multi-Depot Warehouse

Batching of roll containers in an order-picking warehouse is done to exploit similarities in the containers and to introduce savings in both time and distance during a route. The problem is divided in to two parts: path construction and batching. Strict precedence constraints are considered in path construction using an exhaustive branch and bound search algorithm, while batching is done with a simulated annealing combinatorial search. A method for approximating the savings from batching three or more roll containers used as the basis for limiting the calls to 'heavy' routing methods.