Production scheduling in a market-driven foundry: a mathematical programming approach versus a project scheduling metaheuristic algorithm

This paper describes a real problem in a market-driven medium sized foundry delivering a wide range of castings to different markets. The problem consists of finding an efficient production plan to schedule the different processes (moulding, furnacing, cutting, tooling, etc.) needed to the manufacture of the pieces. Different objectives and resources and technical constraints must be taken into account. To solve this problem we have first developed a more classical integer linear programming approach based on a rolling horizon strategy. The most innovative contribution of the paper is that it models the problem as a project scheduling problem. Based on this model we present a metaheuristic algorithm that adapts techniques from the area. Computational experiments comparing both approaches are provided on instances created by a generator simulating real instances.