Thermal energy efficiency evaluation of cutting space for dry cutting machine tools: An exergy time-varying graphical method

Dry cutting technology is one of the future development trends in manufacturing industry. However, its thermal issue is more challenging than wet cutting and substantial energy is required to maintain the thermal stability of cutting space. Besides, the time-varying heat transfer characteristics raise the complexity of thermal energy efficiency evaluation for machine tools. In light of this, the exergy analysis that is suitable for thermal engineering is introduced to address the thermal issue of cutting space for dry cutting machine tools. Firstly, the thermal boundary of cutting space is defined and the thermal balance properties are analyzed. Subsequently, the exergy balance model and exergy destruction model of cutting space are established based on the first and second laws of thermodynamics. Furthermore, an exergy time-varying graphical method is proposed to evaluate the thermal energy efficiency of cutting space. Finally, a case study on a high-speed dry hobbing machine is carried out to verify the feasibility and effectiveness of the proposed methods. The parametric and optimization analyses are conducted to reveal the influence of multi-parameter on evaluation indicators. This study lays a foundation for thermal energy efficiency assessment and energy conversion degradation analysis, and provides theoretical support for the thermal balance control strategies optimizing of machine tools.