An energy saving scheduling MIP formulation for the iron-casting processes in foundries

The sand-casting production process is a type of operation that provides high-energy consumption, so that even a small percentage of energy saving brings to a considerable cost reduction. This work presents a Mixed Integer Programming formulation to optimize the scheduling in cast-iron foundries with two parallel melting lines and a casting line, with the objective to minimize the energy consumption of the furnaces and the waste that occurs when the molten material prepared is not used for casting but is solidified again. The sequence of products entering the process is crucial to minimize these wastes, because the various types of alloys that constitute the different products cannot be mixed, in order not to contaminate each other. Therefore, if there is a residual liquid in the furnace, the residual must be solidified and extracted from the furnace if the subsequent alloy to be processed is different from the residual.