Optimized design of press frames with respect to energy efficiency

Large forming presses require great amounts of construction metal materials. Nevertheless, eco-design principles in the field of forming presses have seldom been confronted in the scientific literature. In this paper, an optimization model is proposed, suitable for designing press frames which are optimal in terms of energy efficiency. First, a framework is proposed for modular and functional description of a machine tool is described, in order to identify the largest energy consuming modules and functions. Then, a simple analytical model of loads, stresses and deformations is proposed for pre-stressed structures. Then, the equations of the analytical models are used as the constraints of a numerical global optimization algorithm, aimed at minimizing the amount of energy stored into the press frame and the extra-energy due to deformation of the columns in the usage lifetime of the press. The results clearly show that, only if the press frame structure is monolithic, it is possible to obtain a solution which is truly optimal. This conclusion is robust with respect to potential noise or uncertainty issues, which in this case are mainly related to the coefficient of the objective functions.