A 4/3-APPROXIMATION ALGORITHM FOR CASSETTE PACKING IN STEEL INDUSTRY

In packing steel products of coils into cassettes, we need to consider both the width and weight capacity of cassettes. Each coil has weight in (0, 1/3] and width in (1/6, 1/3] when scaling both the weight and width capacities to 1. With the objective of minimizing the number of cassettes to pack the coils, the problem is modeled by two-dimensional vector packing. To efficiently pack the coils having sizes specified by the ranges, we develop a 4/3-approximation algorithm.