Maximizing the Number of Slabs Charged in an Aluminium Reheating Furnace by Using a Constraint Logic Programming

摘要

This paper discusses a complex arrangement problem for maximizing the number of charging slabs in an aluminium reheating furnace. It is important to decide the slabs arrangement that many number of slabs can charge into a furnace for improvement of the productivity and reduction of the fuel costs. This problem is similar to the combinatorial optimization problem such as a cutting stock problem or a rectangle-packing problem. But it is quite different from them in considering the constraint of rolling sequence, slab transportation, and change of constraint dynamically when the slabs are extracted from a furnace according to rolling sequence. In this paper, we propose an approach based on a constraint logic programming (CLP). The remarkable points are the addition of redundant constraints and application of slab grouping method to reduce the solution time. The effectiveness of the proposed approach has been confirmed by some numerical experiments to obtain a satisfying solution in a practical time.