A State-of-the-Art Review on Energy–Resource Synergy in Advanced Machining Using Hybrid Lubrication and Thermal Strategies

Energy consumption and resource utilization have become critical challenges in modern machining due to increasing manufacturing costs, stringent environmental regulations, and global carbon-reduction targets. While sustainable machining strategies such as dry machining, minimum quantity lubrication (MQL), and cryogenic cooling have been widely investigated, recent years have witnessed the rapid development of advanced assisted and hybrid machining processes aimed at further reducing energy demand and material waste. However, existing review studies largely focus on individual techniques or lubrication approaches, lacking a systematic perspective on the combined energy–resource saving mechanisms in advanced sustainable machining. This review presents a comprehensive and up-to-date analysis of energy consumption characteristics and resource-saving strategies in advanced sustainable machining processes. Particular attention is given to emerging and hybrid technologies, including ultrasonic-assisted machining, ultrasonic-assisted MQL, electrostatic MQL (eMQL), multi-nozzle MQL systems, nanofluid-based MQL, laser-assisted machining, vortex tube-assisted cooling, dry ice machining, and hybrid cryogenic–MQL strategies such as LN2-MQL and CO2-MQL. The review systematically discusses how these techniques influence energy flow, tool–workpiece interactions, lubrication efficiency, and thermal behavior during machining. Furthermore, this paper highlights the synergistic effects of combining multiple assistance methods, emphasizing their role in achieving simultaneous improvements in productivity, tool life, surface integrity, and sustainability performance. Energy-based metrics, resource efficiency indicators, and carbon emission considerations reported in the literature are critically evaluated to identify current limitations and inconsistencies. Finally, key research gaps and future directions are outlined, including the need for standardized sustainability assessment frameworks, data-driven energy optimization, and intelligent hybrid machining systems. This review aims to provide a valuable reference for researchers and practitioners seeking to design next-generation sustainable machining processes with enhanced energy efficiency and reduced environmental impact.