Abstract: Energy modeling of machine tool is the basis of energy characteristic analysis and energy efficiency improvement. The existing researches of energy model focus on statistic analysis of total energy and the modeling of main transmission system, and the study of mathematical models of all energy flows in a machine tool, especially a CNC machine tool is scarce. The mathematical models of a CNC machine tool from the view of energy breakdown considering the multi-energy-sources feature of a CNC machine tool is analyzed. The multi energy sources of a CNC machine tool are broken up, where the energy sources are classified into cutting and driving system, cutting related auxiliary system, driving related auxiliary system and the other. The energy flow system of a CNC machine tool is advanced based on the power equation analysis of energy flows. And then the systematical mathematical energy model of a CNC machine tool is set up by combining the power equations with the operating features of four kinds of energy sources. The case study shows that the proposed energy model can provide fundamental support for energy efficiency analysis, energy consumption forecasting and energy-saving optimization and so on during the operation process of a CNC machine tool, which has significance in practice.

Key words: CNC machine tool, Energy flow, Energy model, Multi energy sources, Power equation