Simulation-based optimization for steel stacking

Abstract

In many sectors of industry, manufacturers possess warehouses where finished goods are stored, awaiting to fulfill a client order. We present a situation where these items are characterized by release and due dates, i.e. warehouse arrival for storage and client delivery, respectively. The warehouse has a number of positions available, where items can be placed on top of each other, forming stacks. For item manipulation, there is a single a stacking crane, able to carry one item at a time. When in a given stack an item at the top is due at a date later than some item below it, it must be relocated to another stack, so that the item below can be delivered. In this problem the objective is to minimize the number of movements made by the crane.