Maximising benefits in short-term planning in bottle-glass industry

The objective of this paper is to establish a short-term plan that maximizes benefits. A furnace distributes glass to a set of parallel and unrelated machines. The main constraint in this industrial context is that of introducing a new glass color in the furnace, which requires that all machines stop at the same time. Several cases are considered: that lots can be split, preempted or not. It has been shown that when splitting or preemption is allowed, the problem can be solved in polynomial time using linear programming. But when preemption is not allowed, the problem is shown NP-hard. To finish with, we present a hierarchical approach based on aggregation and disaggregation of products.