Some experiments with a simple tabu search algorithm for the manufacturer's pallet loading problem

Abstract

The manufacturer's pallet loading problem consists in arranging, orthogonally and without overlapping, the maximum number of boxes with dimensions ( l, w) or ( w, l) onto a rectangular pallet with dimensions ( L, W). This problem has been successfully handled by block heuristics, which generate loading patterns composed by one or more blocks where the boxes have the same orientation. A common feature of such methods is that the solutions provided are limited to the so-called first order non-guillotine patterns. In this paper we propose an approach based on the incorporation of simple tabu search (without longer-term memory structures) in block heuristics. Starting from an initial loading pattern, the algorithm performs moves that increase the size of selected blocks in the current pattern; as a result, other blocks are decreased, eliminated or created. Computational results indicate that the approach is capable of generating superior order optimal patterns for difficult instances reported in the literature.