Using Simulation To Assess The Effectiveness Of Pallet Stacking Methods

Stacking objects onto pallets is the most widely used method of bulk shipping, accounting for over 60% of the volume of goods shipped worldwide. Due in part to the wide variation in size, shape and weight of objects to be palletized, successful stacking is more of an art than a science. Pallet stacking is an example of the three dimensional cutting stock problem, a variant of the combinatorial NP-hard knapsack problem. This makes it hard to find a common heuristic to satisfy requirements for major shippers and receivers. In this paper, we explore the role that simulation can play in comparing how well automated metrics can gauge the quality of a pallet. A physics enabled simulator allows us to study the interlocking among hidden internal boxes and makes it possible to study metrics that cannot be determined by mere statistics. Results from a competition held in May 2010 are used to illustrate the concepts.