Analysis of energy consumption in CNC machining centers and determination of optimal cutting conditions

Abstract

This paper deals with the minimization of machine tool (CNC milling centre) energy consumption during the usage phase. This study shows that the selection of the main process parameters can entail energy savings in manufacturing metal components. The analysis exploits a developed and experimentally updated energy consumption analytical model. The main analyzed machine functional modules (spindle, axis, chillers, tool change system, auxiliaries and the cutting process) are described in terms of power adsorption and energy usage. The global energy consumption function, as the summation of the energetic consumption of the listed machine tool components, is expressed in a closed analytical form and then it is numerically optimized to find out the cutting conditions (basically cutting speed and feed rate) that satisfy the minimum energy criteria. The optimization procedure takes into account the wear of the tool and the energy required to produce the tools itself. The numerical results reported in this work refer to the face milling of an aluminum prismatic workpiece. In the analyzed case, the identified optimal conditions are compared to those obtained following the production time minimization criteria.