Energy efficiency analysis of machine tools with periodic maintenance

Machine tools consume a large amount of energy in the production process. Effective reduction of energy consumption of the machine tool will lead to significant savings. Although substantial efforts have been devoted to reducing energy consumption of the machine tool through upgrading the equipment or improving the manufacturing process, the study of energy efficiency improvement through effective maintenance operations scheduling has received significantly less attention. Power consumption usually increases as the machine tool deteriorates in most mechanical manufacturing environments. In this paper, we develop a discrete-time, discrete-state homogeneous Markov chain of the deteriorating machine tool based on energy efficiency. To evaluate the energy performance and productivity performance of the machine tool with periodic maintenance, analytical models of average energy efficiency and average productivity are developed based on renewal reward theorem. The effects of some parameters on the average energy efficiency are analysed through a numerical example, and the trade-off between energy efficiency and productivity is discussed.