Optimization of automated float glass lines

In automated float glass manufacturing, a continuous ribbon of glass is cut according to customer orders and then offloaded using robots. We consider the problem of laying out and sequencing the orders on the ribbon so as to minimize waste. The problem combines characteristics of cutting, packing, and sequencing problems. Given the size and the complexity of the problem, we propose a two-phase heuristic approach where the layout and sequencing aspects of the problem are addressed independently. On a set of real-world and random instances, our approach achieves schedules with over 99% yield (ratio of glass input and output). This is a significant improvement for the manufacturer where this work has been implemented.