2002 Volume 15 Issue 8 Pages 438-446
This paper discusses a complex arrangement problem for maximizing the number of charging slabs for an aluminum reheating furnaces. It is important to decide the slabs arrangement that many number of slabs enable to charge into a furnace to improve the productivity and reduce the fuel costs. Usually, the meta-heuristic approach for instance genetic algorithm (GA) or the simulated annealing (SA) has been used to solve the combinatorial optimization problem such as a cutting stock problem or a rectangle-packing problem. This problem is similar to above problems, 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 constraint logic programming (CLP) based approach. The remarkable points of this approach are the addition of redundant constraints, application of slab grouping method and so on to improve the solution time. We confirm the effectiveness of the proposed approach by numerical experiments and show that it can obtain a good solution in practical time.