Empirical modeling and simultaneous optimization of energy efficiency/demand, cost and productivity in incremental forming of metallic clad composite

Energy, cost and productivity are basic sustainability and performance indicators of a manufacturing process. This study methodically analyzes these indicators as function of processing parameters for Incremental Sheet Forming (ISF) of a metallic clad composite with three layers. The results show that the said quantities and components of power/energy are sensitive to technological parameters in a highly interactive way. Furthermore, it is imperative to employ high values of step size and feed rate, and low values of wall angle, spindle rotation and annealing temperature in order to simultaneously reduce cost and energy demand and to enhance productivity. An indicator (E-fraction) to gauge process and machine performance in respect of energy efficiency is introduced and analyzed. Its value depending on the parameters is found to vary from 0.07 to 0.53. The energy cost ranges from 0.18% to 0.69% of total product cost, which has been observed to vary from 10.6 eur to 41 eur. In order for the ISF users to estimate the power requirement (solely due to forming) to select an appropriate machine tool to process clad sheet and to know the productivity index along with cost impact on the customers, prediction models are proposed. Moreover, optimum conditions simultaneously minimizing energy demand and cost and maximizing productivity are determined.