Method for production design and operations scheduling for plate design in the steel industry

Abstract

An automated method optimally designs plates to satisfy an order book at a steel plant so as to maximize the yield of the plates designed while using capacity fully to reduce the production of surplus slabs or plates, and satisfy order deadlines. Our method consists of four main components: (1) mother plate design, (2) slab design, (3) cast design, and (4) material allocation. A column generation framework for mother plate design is used where the problem is decomposed into a master problem and a subproblem. The master problem is used to evaluate packing patterns that should be used to fulfill the order book and the subproblem generates potential one-dimensional and two-dimensional feasible packing patterns as candidates to be evaluated by the master problem. The solution to the master problem produces a list of mother plates that need to be produced. These mother plates are transformed into candidate slabs, which are represented via an interval graph. The maximal cliques in the interval graph—maximal subsets of slabs which can be grouped together to form casts—are enumerated to generate candidate casts, from which redesign information is sent to the plate/slab design processes. The cast design process is integrated with the plate design/slab design processes in the sense that information is passed from the plate/slab design processes to the cast design process and vice versa. Finally, our method has a material allocation component to assign order plates to inventory mother-plates and slabs.