A two-phase roll cutting problem

A two-phase roll cutting problem appearing in the iron and steel industry is considered in this paper. It consists of optimizing the planning of roll cutting that, for technological reasons, is effected in two phases, i.e., each raw material roll is cut into intermediate primary rolls, which in turn are cut to obtain the constituent rolls of the final product. Apart from an inherent complexity to the cutting problem resulting from the large variety of final product dimensions, other supplementary difficulties also exist. These are related to the existence of numerous restrictions involved in the whole process and the link between the two cutting phases. A heuristic was developed and tested, that is based on an auotmatic sequential search with defined objectives, so as to obtain a good compromise between pattern usage and trim loss, respecting the various technological impositions. Finally, a real example taken from the steel industry together with the solution obtained from a computerized version developed for microcomputers, is presented.